WO2021060913A1 - Method for receiving, by terminal, physical downlink control channel in unlicensed band and apparatus therfor - Google Patents

Abstract

The present disclosure discloses a method for receiving, by a terminal, a physical downlink control channel (PDCCH) in an unlicensed band. In particular, the method comprises transmitting, to a base station, a message A including a first physical random access channel (PRACH) and a first physical uplink shared channel (PUSCH), according to transmission power set by a power ramping counter, and performing a random access procedure (RACH procedure) on the base station by receiving, from the base station, a message B related to contention resolution in response to the message A, wherein a value of the power ramping counter may increase on the basis that a transmission spatial beam for transmission of the message A is configured identically to a transmission spatial beam related to transmission of a PRACH prior to the message A.

Description

Method for receiving downlink control channel by terminal in unlicensed band and apparatus therefor

The present disclosure relates to a method for a UE to receive a downlink control channel in an unlicensed band and an apparatus therefor. More specifically, a UE performs a random access procedure in an unlicensed band and downlink based on a Discontinuous Reception (DRX) operation. It relates to a method for receiving a link control channel and an apparatus therefor.

5G can complement fiber-to-the-home (FTTH) and cable-based broadband (or DOCSIS) as a means of providing streams rated at hundreds of megabits per second to gigabits per second. This high speed is required to deliver TVs in 4K or higher (6K, 8K and higher) resolutions, as well as virtual and augmented reality. Virtual Reality (VR) and Augmented Reality (AR) applications involve almost immersive sports events. Certain application programs may require special network settings. For example, for VR games, game companies may need to integrate core servers with network operators' edge network servers to minimize latency.

Automotive is expected to be an important new driving force in 5G, with many use cases for mobile communication to vehicles. For example, entertainment for passengers demands simultaneous high capacity and high mobility mobile broadband. The reason is that future users will continue to expect high-quality connections, regardless of their location and speed. Another use case in the automotive field is an augmented reality dashboard. It identifies an object in the dark on top of what the driver sees through the front window, and displays information that tells the driver about the distance and movement of the object overlaid. In the future, wireless modules enable communication between vehicles, exchange of information between the vehicle and the supporting infrastructure, and exchange of information between the vehicle and other connected devices (eg, devices carried by pedestrians). The safety system can lower the risk of an accident by guiding the driver through alternative courses of action to make driving safer. The next step will be a remote controlled or self-driven vehicle. This requires very reliable and very fast communication between different self-driving vehicles and between the vehicle and the infrastructure. In the future, self-driving vehicles will perform all driving activities, and drivers will be forced to focus only on traffic anomalies that the vehicle itself cannot identify. The technical requirements of self-driving vehicles require ultra-low latency and ultra-fast reliability to increase traffic safety to levels unachievable by humans.

Smart cities and smart homes, referred to as smart society, will be embedded with high-density wireless sensor networks. A distributed network of intelligent sensors will identify the conditions for cost and energy-efficient maintenance of a city or home. A similar setup can be done for each household. Temperature sensors, window and heating controllers, burglar alarms and appliances are all wirelessly connected. Many of these sensors are typically low data rate, low power and low cost. However, for example, real-time HD video may be required in certain types of devices for surveillance.

The consumption and distribution of energy including heat or gas is highly decentralized, requiring automated control of distributed sensor networks. The smart grid interconnects these sensors using digital information and communication technologies to gather information and act accordingly. This information can include the behavior of suppliers and consumers, enabling smart grids to improve efficiency, reliability, economics, sustainability of production and the distribution of fuels such as electricity in an automated way. The smart grid can also be viewed as another low-latency sensor network.

The health sector has many applications that can benefit from mobile communications. The communication system can support telemedicine providing clinical care from remote locations. This can help reduce barriers to distance and improve access to medical services that are not consistently available in remote rural areas. It is also used to save lives in critical care and emergencies. A wireless sensor network based on mobile communication can provide sensors and remote monitoring of parameters such as heart rate and blood pressure.

Wireless and mobile communications are becoming increasingly important in industrial applications. Wiring is expensive to install and maintain. Thus, the possibility of replacing cables with reconfigurable wireless links is an attractive opportunity for many industries. However, achieving this requires that the wireless connection operates with a delay, reliability and capacity similar to that of the cable, and its management is simplified. Low latency and very low error probability are new requirements that need to be connected to 5G.

Logistics and freight tracking are important use cases for mobile communications that enable tracking of inventory and packages anywhere using location-based information systems. Logistics and freight tracking use cases typically require low data rates, but require a wide range and reliable location information.

The present disclosure is to provide a method for a UE to perform a random access procedure and receive a downlink control channel based on a discontinuous reception (DRX) operation, and an apparatus therefor.

The technical problems to be achieved in the present disclosure are not limited to the technical problems mentioned above, and other technical problems that are not mentioned will be clearly understood by those of ordinary skill in the technical field to which the present invention belongs from the following description. I will be able to.

In the method for receiving a downlink control channel (Physical Downlink Control Channel; PDCCH) in an unlicensed band according to an embodiment of the present disclosure, PSS (Primary Synchronization Signal), SSS (Secondary Synchronization Signal), and PBCH Receives an SS/PBCH (Synchronization Signal/PBCH) block including (Physical Broadcast Channel) from the base station, and is set by a power ramping counter based on system information included in the PBCH of the SS/PBCH block. A message A including a first physical random access channel (PRACH) and a first physical uplink shared channel (PUSCH) is transmitted to the base station according to transmission power, and related to contention resolution in response to the message A. Based on a point in which message B is received from the base station, a random access procedure (RACH procedure) is performed for the base station, and DRX (Discontinuous Reception) is set in the terminal, On- The PDCCH is received from the base station in duration, and the value of the power ramping counter is the same as the transmission spatial beam related to transmission of the PRACH before the message A. It can be increased based on the point that it is composed of.

In this case, the value of the power ramping counter may increase based on the fact that the Listen Before Talk (LBT) for the message A has not failed.

In addition, transmission of the message A may correspond to retransmission of the message A.

In addition, Listen Before Talk (LBT) related to the PRACH may fail.

In addition, based on the fact that the transmission spatial beam for transmission of the message A is configured differently from the transmission spatial beam related to transmission of the PRACH before the message A, the value of the power ramping counter may not increase.

In addition, the power ramping counter may be used to set the transmission power based on the fact that the first PRACH and the first PUSCH are transmitted together through the message A.

A terminal receiving a downlink control channel (PDCCH) in an unlicensed band according to the present disclosure, comprising: at least one transceiver; At least one processor; And at least one memory that is operably connected to the at least one processor and stores instructions for causing the at least one processor to perform a specific operation when executed, wherein the specific operation is PSS System information included in the PBCH of the SS/PBCH block by receiving an SS/PBCH (Synchronization Signal/PBCH) block including (Primary Synchronization Signal), SSS (Secondary Synchronization Signal) and PBCH (Physical Broadcast Channel) from the base station On the basis of, a message A including a first physical random access channel (PRACH) and a first physical uplink shared channel (PUSCH) is transmitted to the base station according to transmission power set by a power ramping counter, and the Receiving message B related to contention resolution from the base station in response to message A, performing a random access procedure (RACH procedure) for the base station, and DRX (Discontinuous Reception) to the terminal The PDCCH is received from the base station in on-duration according to the DRX, based on the point at which is set, and the value of the power ramping counter is the transmission spatial beam for transmission of the message A. It can be increased based on the fact that it is configured in the same manner as the transmission spatial beam related to transmission of the PRACH before the message A.

In this case, the value of the power ramping counter may increase based on the fact that the Listen Before Talk (LBT) for the message A has not failed.

In addition, transmission of the message A may correspond to retransmission of the message A.

In addition, Listen Before Talk (LBT) related to the PRACH may fail.

In addition, based on the fact that the transmission spatial beam for transmission of the message A is configured differently from the transmission spatial beam related to transmission of the PRACH before the message A, the value of the power ramping counter may not increase.

In addition, the power ramping counter may be used to set the transmission power based on the fact that the first PRACH and the first PUSCH are transmitted together through the message A.

An apparatus for receiving a downlink control channel (PDCCH) in an unlicensed band according to the present disclosure, the apparatus comprising: at least one transceiver; At least one processor; And at least one memory that is operably connected to the at least one processor and stores instructions for causing the at least one processor to perform a specific operation when executed, wherein the specific operation is PSS Receives a SS/PBCH (Synchronization Signal/PBCH) block including (Primary Synchronization Signal), SSS (Secondary Synchronization Signal) and PBCH (Physical Broadcast Channel), and based on system information included in the PBCH of the SS/PBCH block Accordingly, message A including a first physical random access channel (PRACH) and a first physical uplink shared channel (PUSCH) is transmitted according to the transmission power set by a power ramping counter, and a response to the message A By receiving message B related to contention resolution, performing a random access procedure (RACH procedure), and based on the point that DRX (Discontinuous Reception) is set in the device, according to the DRX The PDCCH is received in on-duration, and the value of the power ramping counter is the same as the transmission spatial beam related to transmission of the PRACH prior to the message A. It can be increased based on what is constructed.

In a method for a base station to transmit a downlink control channel (PDCCH) in an unlicensed band according to an embodiment of the present disclosure, a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a PBCH The SS/PBCH (Synchronization Signal/PBCH) block including (Physical Broadcast Channel) is transmitted to the terminal, and message A including a first PRACH (Physical Random Access Channel) and a first PUSCH (Physical Uplink Shared Channel) is described above. Receiving from the terminal, in response to the message A, transmitting a message B related to contention resolution to the terminal, and transmitting the PDCCH to the terminal in On-duration for DRX (Discontinuous Reception) operation Including, the transmission power of the message A is set based on a power ramping counter (ramping counter), the value of the power ramping counter is, a transmission spatial beam for transmission of the message A is the message It may increase based on the fact that it is configured in the same manner as the transmission spatial beam related to transmission of the PRACH before A.

In a computer-readable storage medium according to an embodiment of the present disclosure, the computer-readable storage medium, when executed by at least one processor, provides instructions for causing the at least one processor to perform operations for a user device. Stores at least one computer program including, and the operations receive a SS/PBCH (Synchronization Signal/PBCH) block including a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH). And, based on the system information included in the PBCH of the SS/PBCH block, a first PRACH (Physical Random Access Channel) and a first PUSCH (Physical Uplink Shared Channel) according to transmission power set by a power ramping counter ) And transmits a message A, and receives a message B related to contention resolution in response to the message A, performs a random access procedure (RACH procedure), and performs a Discontinuous Reception (DRX). ) Is set, a downlink control channel (PDCCH) is received in On-duration according to the DRX, and the value of the power ramping counter is a transmission space for transmission of the message A. The beam (transmission spatial beam) may be increased based on the fact that the transmission spatial beam related to the transmission of the PRACH before the message A is configured in the same manner.

According to the present disclosure, a terminal can efficiently receive a downlink control channel in an unlicensed band.

The effects obtainable in the present disclosure are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those of ordinary skill in the art from the following description. will be.

1 to 4 illustrate examples of various wireless devices to which embodiments of the present disclosure are applied.

5 shows an example of a communication system to which embodiments of the present disclosure are applied.

6 is a diagram for describing an embodiment of a discontinuous reception (DRX) operation.

7 is a diagram illustrating physical channels used in a 3GPP system and a general signal transmission method using them.

8 to 10 are diagrams for explaining channel transmission in an unlicensed band.

11 to 16 are diagrams for explaining a composition and a transmission method of an SS/PBCH block.

17 is a diagram showing a basic process of a 2-step RACH.

FIG. 18 is a diagram illustrating an embodiment of transmission of Msg A according to whether a terminal succeeds or fails in an LBT and a configuration of a transmission beam direction.

19 is a diagram illustrating an embodiment of the present disclosure in which a power ramping counter is maintained or increased according to a transmission beam direction of a terminal.

20 to 21 are diagrams for explaining an example of implementing specific operations of a terminal and a base station according to an embodiment of the present disclosure.

22 is a diagram illustrating an operation flow of a terminal and a base station for performing a 2-step RACH procedure based on embodiments of the present disclosure.

The configuration, operation, and other features of the present invention may be easily understood by the embodiments of the present invention described with reference to the accompanying drawings. The embodiments described below are examples in which the technical features of the present invention are applied to a 3GPP system.

Although this specification describes an embodiment of the present invention using an LTE system, an LTE-A system, and an NR system, this is an example and the embodiment of the present invention can be applied to any communication system corresponding to the above definition.

In addition, in the present specification, the name of the base station may be used as a generic term including a remote radio head (RRH), an eNB, a transmission point (TP), a reception point (RP), a relay, and the like.

3GPP-based communication standards include downlink physical channels corresponding to resource elements carrying information originating from higher layers, and downlink corresponding to resource elements used by the physical layer but not carrying information originating from higher layers. Physical signals are defined. For example, a physical downlink shared channel (PDSCH), a physical broadcast channel (PBCH), a physical multicast channel (PMCH), a physical control format indicator channel (physical control) A format indicator channel, PCFICH), a physical downlink control channel (PDCCH), and a physical hybrid ARQ indicator channel (PHICH) are defined as downlink physical channels, and a reference signal and a synchronization signal Is defined as downlink physical signals. A reference signal (RS), also referred to as a pilot, refers to a signal of a predefined special waveform that the gNB and the UE know each other. For example, cell specific RS (RS), UE- Specific RS (UE-specific RS, UE-RS), positioning RS (positioning RS, PRS), and channel state information RS (channel state information RS, CSI-RS) are defined as a downlink reference signal. The 3GPP LTE/LTE-A standard corresponds to uplink physical channels corresponding to resource elements carrying information originating from an upper layer, and resource elements used by the physical layer but not carrying information originating from an upper layer. Uplink physical signals are defined. For example, a physical uplink shared channel (PUSCH), a physical uplink control channel (PUCCH), and a physical random access channel (PRACH) are used as uplink physical channels. It is defined, and a demodulation reference signal (DMRS) for an uplink control/data signal and a sounding reference signal (SRS) used for uplink channel measurement are defined.

In the present invention, PDCCH (Physical Downlink Control CHannel) / PCFICH (Physical Control Format Indicator CHannel) / PHICH ((Physical Hybrid automatic retransmit request Indicator CHannel) / PDSCH (Physical Downlink Shared CHannel) is DCI (Downlink Control Information) / CFI ( Control Format Indicator) / Downlink ACK / NACK (ACKnowlegement / Negative ACK) / refers to a set of time-frequency resources carrying downlink data or a set of resource elements. Uplink Shared CHannel)/PRACH (Physical Random Access CHannel) refers to a set of time-frequency resources or a set of resource elements each carrying uplink control information (UCI)/uplink data/random access signals. , PDCCH/PCFICH/PHICH/PDSCH/PUCCH/PUSCH/PRACH assigned to or belonging to a time-frequency resource or resource element (RE), respectively, PDCCH/PCFICH/PHICH/PDSCH/PUCCH/PUSCH/PRACH RE or PDCCH It is referred to as /PCFICH/PHICH/PDSCH/PUCCH/PUSCH/PRACH resource.In the following, the expression that the user equipment transmits PUCCH/PUSCH/PRACH is, respectively, uplink control information/uplink data on or through PUSCH/PUCCH/PRACH. /It is used in the same meaning as that of transmitting a random access signal.In addition, the expression that gNB transmits PDCCH/PCFICH/PHICH/PDSCH is, respectively, on PDCCH/PCFICH/PHICH/PDSCH. It is used in the same meaning as transmitting downlink data/control information through or through.

Hereinafter, CRS/DMRS/CSI-RS/SRS/UE-RS are allocated or configured OFDM symbols/subcarriers/REs are CRS/DMRS/CSI-RS/SRS/UE-RS symbols/carriers. It is called /subcarrier/RE. For example, an OFDM symbol to which a tracking RS (TRS) is allocated or configured is referred to as a TRS symbol, and a subcarrier to which a TRS is allocated or configured is referred to as a TRS subcarrier, and a TRS is allocated. Alternatively, the configured RE is referred to as TRS RE. In addition, a subframe configured for TRS transmission is referred to as a TRS subframe. In addition, a subframe in which a broadcast signal is transmitted is called a broadcast subframe or a PBCH subframe, and a subframe in which a synchronization signal (eg, PSS and/or SSS) is transmitted is a synchronization signal subframe or a PSS/SSS subframe. It is called. The OFDM symbols/subcarriers/REs to which PSS/SSS are allocated or configured are referred to as PSS/SSS symbols/subcarriers/REs, respectively.

In the present invention, a CRS port, a UE-RS port, a CSI-RS port, and a TRS port respectively refer to an antenna port configured to transmit a CRS, an antenna port configured to transmit a UE-RS, Refers to an antenna port configured to transmit CSI-RS and an antenna port configured to transmit TRS. The antenna ports configured to transmit CRSs can be classified according to the positions of the REs occupied by the CRS according to the CRS ports, and the antenna ports configured to transmit UE-RSs are the UE -According to the RS ports, the positions of the REs occupied by the UE-RS can be distinguished from each other, and the antenna ports configured to transmit CSI-RSs are occupied by the CSI-RS according to the CSI-RS ports. It can be distinguished from each other by the location of the REs. Therefore, the term CRS/UE-RS/CSI-RS/TRS port is also used as a term that refers to a pattern of REs occupied by CRS/UE-RS/CSI-RS/TRS within a certain resource area.

1 illustrates a wireless device applicable to the present invention.

Referring to FIG. 1, the first wireless device 100 and the second wireless device 200 may transmit and receive wireless signals through various wireless access technologies (eg, LTE and NR). Here, {the first wireless device 100, the second wireless device 200} is the {wireless device 100x, the base station 200} and/or {wireless device 100x, wireless device 100x) of FIG. 5 } Can be matched.

The first wireless device 100 includes one or more processors 102 and one or more memories 104, and may further include one or more transceivers 106 and/or one or more antennas 108. The processor 102 controls the memory 104 and/or the transceiver 106 and may be configured to implement the descriptions, functions, procedures, suggestions, methods, and/or operational flowcharts disclosed herein. For example, the processor 102 may process information in the memory 104 to generate first information/signal, and then transmit a radio signal including the first information/signal through the transceiver 106. In addition, the processor 102 may store information obtained from signal processing of the second information/signal in the memory 104 after receiving a radio signal including the second information/signal through the transceiver 106. The memory 104 may be connected to the processor 102 and may store various information related to the operation of the processor 102. For example, the memory 104 may perform some or all of the processes controlled by the processor 102, or instructions for performing the descriptions, functions, procedures, suggestions, methods, and/or operational flow charts disclosed herein. It is possible to store software code including: Here, the processor 102 and the memory 104 may be part of a communication modem/circuit/chip designed to implement a wireless communication technology (eg, LTE, NR). The transceiver 106 may be coupled with the processor 102 and may transmit and/or receive radio signals through one or more antennas 108. Transceiver 106 may include a transmitter and/or a receiver. The transceiver 106 may be mixed with an RF (Radio Frequency) unit. In the present invention, the wireless device may mean a communication modem/circuit/chip.

Specifically, commands and/or operations controlled by the processor 102 of the first wireless device 100 according to an embodiment of the present invention and stored in the memory 104 will be described.

The following operations are described based on the control operation of the processor 102 from the perspective of the processor 102, but may be stored in the memory 104 in software code or the like for performing these operations.

The processor 102 may control the transceiver 106 to transmit a message A including a Physical Random Access Channel (PRACH) and a Physical Uplink Shared Channel (PUSCH). In addition, the processor 102 may control the transceiver 106 to receive a message B including contention resolution information in response to the message A. In this case, a specific operation method of the processor 102 described above may be based on embodiments to be described later.

Specifically, commands and/or operations controlled by the processor 202 of the second wireless device 200 according to an embodiment of the present invention and stored in the memory 204 will be described.

The following operations are described based on the control operation of the processor 202 from the perspective of the processor 202, but may be stored in the memory 204, such as software code for performing these operations.

The processor 202 may control the transceiver 206 to receive a message A including a physical random access channel (PRACH) and a physical uplink shared channel (PUSCH) from the first wireless device 100. The processor 202 may control the transceiver 206 to transmit, in response to the message A, message B including contention resolution information. In this case, a specific operation method of the processor 202 may be based on embodiments to be described later.

Hereinafter, hardware elements of the wireless devices 100 and 200 will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors 102, 202. For example, one or more processors 102 and 202 may implement one or more layers (eg, functional layers such as PHY, MAC, RLC, PDCP, RRC, and SDAP). One or more processors 102, 202 may be configured to generate one or more Protocol Data Units (PDUs) and/or one or more Service Data Units (SDUs) according to the description, functions, procedures, proposals, methods, and/or operational flow charts disclosed in this document. Can be generated. One or more processors 102, 202 may generate messages, control information, data, or information according to the description, function, procedure, proposal, method, and/or operational flow chart disclosed herein. At least one processor (102, 202) generates a signal (e.g., a baseband signal) containing PDU, SDU, message, control information, data or information according to the functions, procedures, proposals and/or methods disclosed in this document. , Can be provided to one or more transceivers (106, 206). One or more processors 102, 202 may receive signals (e.g., baseband signals) from one or more transceivers 106, 206, and the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed herein PDUs, SDUs, messages, control information, data, or information may be obtained according to the parameters.

One or more of the processors 102 and 202 may be referred to as a controller, microcontroller, microprocessor, or microcomputer. One or more of the processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs) May be included in one or more processors 102 and 202. The description, functions, procedures, suggestions, methods, and/or operational flowcharts disclosed in this document may be implemented using firmware or software, and firmware or software may be implemented to include modules, procedures, functions, and the like. The description, functions, procedures, proposals, methods and/or operational flow charts disclosed in this document are configured to perform firmware or software included in one or more processors 102, 202, or stored in one or more memories 104, 204, and It may be driven by the above processors 102 and 202. The descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this document may be implemented using firmware or software in the form of codes, instructions, and/or sets of instructions.

One or more memories 104, 204 may be connected to one or more processors 102, 202, and may store various types of data, signals, messages, information, programs, codes, instructions and/or instructions. One or more of the memories 104 and 204 may be composed of ROM, RAM, EPROM, flash memory, hard drive, registers, cache memory, computer readable storage media, and/or combinations thereof. One or more memories 104 and 204 may be located inside and/or outside of one or more processors 102 and 202. In addition, one or more memories 104, 204 may be connected to one or more processors 102, 202 through various technologies such as wired or wireless connection.

One or more transceivers 106 and 206 may transmit user data, control information, radio signals/channels, and the like mentioned in the methods and/or operation flow charts of this document to one or more other devices. One or more transceivers (106, 206) may receive user data, control information, radio signals/channels, etc., mentioned in the description, functions, procedures, proposals, methods and/or operational flowcharts disclosed in this document from one or more other devices. have. For example, one or more transceivers 106 and 206 may be connected to one or more processors 102 and 202 and may transmit and receive wireless signals. For example, one or more processors 102, 202 may control one or more transceivers 106, 206 to transmit user data, control information, or radio signals to one or more other devices. In addition, one or more processors 102, 202 may control one or more transceivers 106, 206 to receive user data, control information, or radio signals from one or more other devices. In addition, one or more transceivers (106, 206) may be connected to one or more antennas (108, 208), one or more transceivers (106, 206) through the one or more antennas (108, 208), the description and functions disclosed in this document. It may be set to transmit and receive user data, control information, radio signals/channels, and the like mentioned in a procedure, a proposal, a method, and/or an operation flow chart. In this document, one or more antennas may be a plurality of physical antennas or a plurality of logical antennas (eg, antenna ports). One or more transceivers (106, 206) in order to process the received user data, control information, radio signal / channel, etc. using one or more processors (102, 202), the received radio signal / channel, etc. in the RF band signal. It can be converted into a baseband signal. One or more transceivers 106 and 206 may convert user data, control information, radio signals/channels, etc. processed using one or more processors 102 and 202 from a baseband signal to an RF band signal. To this end, one or more of the transceivers 106 and 206 may include (analog) oscillators and/or filters.

2 shows another example of a wireless device applied to the present invention. The wireless device may be implemented in various forms according to use-examples/services (see FIG. 5).

Referring to FIG. 2, the wireless devices 100 and 200 correspond to the wireless devices 100 and 200 of FIG. 1, and various elements, components, units/units, and/or modules ). For example, the wireless devices 100 and 200 may include a communication unit 110, a control unit 120, a memory unit 130, and an additional element 140. The communication unit may include a communication circuit 112 and a transceiver(s) 114. For example, the communication circuit 112 may include one or more processors 102,202 and/or one or more memories 104,204 of FIG. 1. For example, the transceiver(s) 114 may include one or more transceivers 106,206 and/or one or more antennas 108,208 of FIG. 1. The control unit 120 is electrically connected to the communication unit 110, the memory unit 130, and the additional element 140 and controls all operations of the wireless device. For example, the control unit 120 may control the electrical/mechanical operation of the wireless device based on the program/code/command/information stored in the memory unit 130. In addition, the control unit 120 transmits the information stored in the memory unit 130 to an external (eg, other communication device) through the communication unit 110 through a wireless/wired interface, or externally through the communication unit 110 (eg, Information received through a wireless/wired interface from another communication device) may be stored in the memory unit 130. Accordingly, the specific operation process of the control unit 120 and the program/code/command/information stored in the memory unit 130 according to the present invention are at least one of the processors 102 and 202 of FIG. 2 and the memory 104 and 204. ) May correspond to at least one of the operations.

The additional element 140 may be configured in various ways depending on the type of wireless device. For example, the additional element 140 may include at least one of a power unit/battery, an I/O unit, a driving unit, and a computing unit. Although not limited thereto, wireless devices include robots (FIGS. 5, 100a), vehicles (FIGS. 5, 100b-1, 100b-2), XR devices (FIGS. 5, 100c), portable devices (FIGS. 5, 100d), and home appliances. (FIGS. 5, 100e), IoT devices (FIGS. 5, 100f), digital broadcasting terminals, hologram devices, public safety devices, MTC devices, medical devices, fintech devices (or financial devices), security devices, climate/environment devices, It may be implemented in the form of an AI server/device (FIGS. 5 and 400), a base station (FIGS. 5 and 200), and a network node. The wireless device can be used in a mobile or fixed place depending on the use-example/service.

In FIG. 2, various elements, components, units/units, and/or modules in the wireless devices 100 and 200 may be entirely interconnected through a wired interface, or at least some may be wirelessly connected through the communication unit 110. For example, in the wireless devices 100 and 200, the control unit 120 and the communication unit 110 are connected by wire, and the control unit 120 and the first unit (eg, 130, 140) are connected through the communication unit 110. Can be connected wirelessly. In addition, each element, component, unit/unit, and/or module in the wireless device 100 and 200 may further include one or more elements. For example, the control unit 120 may be configured with one or more processor sets. For example, the control unit 120 may be composed of a set of a communication control processor, an application processor, an electronic control unit (ECU), a graphic processing processor, and a memory control processor. As another example, the memory unit 130 includes random access memory (RAM), dynamic RAM (DRAM), read only memory (ROM), flash memory, volatile memory, and non-volatile memory. volatile memory) and/or a combination thereof.

Hereinafter, an implementation example of FIG. 2 will be described in more detail with reference to the drawings.

3 illustrates a portable device applied to the present invention. Portable devices may include smart phones, smart pads, wearable devices (eg, smart watches, smart glasses), and portable computers (eg, notebook computers). The portable device may be referred to as a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a subscriber station (SS), an advanced mobile station (AMS), or a wireless terminal (WT).

3, the portable device 100 includes an antenna unit 108, a communication unit 110, a control unit 120, a memory unit 130, a power supply unit 140a, an interface unit 140b, and an input/output unit 140c. ) Can be included. The antenna unit 108 may be configured as a part of the communication unit 110. Blocks 110 to 130/140a to 140c correspond to blocks 110 to 130/140 of FIG. 2, respectively.

The communication unit 110 may transmit and receive signals (eg, data, control signals, etc.) with other wireless devices and base stations. The controller 120 may perform various operations by controlling components of the portable device 100. The controller 120 may include an application processor (AP). The memory unit 130 may store data/parameters/programs/codes/commands required for driving the portable device 100. In addition, the memory unit 130 may store input/output data/information, and the like. The power supply unit 140a supplies power to the portable device 100 and may include a wired/wireless charging circuit, a battery, and the like. The interface unit 140b may support connection between the portable device 100 and other external devices. The interface unit 140b may include various ports (eg, audio input/output ports, video input/output ports) for connection with external devices. The input/output unit 140c may receive or output image information/signal, audio information/signal, data, and/or information input from a user. The input/output unit 140c may include a camera, a microphone, a user input unit, a display unit 140d, a speaker, and/or a haptic module.

For example, in the case of data communication, the input/output unit 140c acquires information/signals (eg, touch, text, voice, image, video) input from the user, and the obtained information/signals are stored in the memory unit 130. Can be saved. The communication unit 110 may convert the information/signal stored in the memory into a wireless signal, and may directly transmit the converted wireless signal to another wireless device or to a base station. In addition, after receiving a radio signal from another radio device or a base station, the communication unit 110 may restore the received radio signal to the original information/signal. After the restored information/signal is stored in the memory unit 130, it may be output in various forms (eg, text, voice, image, video, heptic) through the input/output unit 140c.

4 illustrates a vehicle or an autonomous vehicle applied to the present invention. The vehicle or autonomous vehicle may be implemented as a mobile robot, a vehicle, a train, an aerial vehicle (AV), a ship, or the like.

Referring to FIG. 4, the vehicle or autonomous vehicle 100 includes an antenna unit 108, a communication unit 110, a control unit 120, a driving unit 140a, a power supply unit 140b, a sensor unit 140c, and autonomous driving. It may include a unit (140d). The antenna unit 108 may be configured as a part of the communication unit 110. Blocks 110/130/140a to 140d correspond to blocks 110/130/140 of FIG. 2, respectively.

The communication unit 110 may transmit and receive signals (eg, data, control signals, etc.) with external devices such as other vehicles, base stations (e.g. base stations, roadside base stations, etc.), and servers. The controller 120 may perform various operations by controlling elements of the vehicle or the autonomous vehicle 100. The control unit 120 may include an Electronic Control Unit (ECU). The driving unit 140a may cause the vehicle or the autonomous vehicle 100 to travel on the ground. The driving unit 140a may include an engine, a motor, a power train, a wheel, a brake, a steering device, and the like. The power supply unit 140b supplies power to the vehicle or the autonomous vehicle 100, and may include a wired/wireless charging circuit, a battery, and the like. The sensor unit 140c may obtain vehicle status, surrounding environment information, user information, and the like. The sensor unit 140c is an IMU (inertial measurement unit) sensor, a collision sensor, a wheel sensor, a speed sensor, an inclination sensor, a weight detection sensor, a heading sensor, a position module, and a vehicle advancement. /Reverse sensor, battery sensor, fuel sensor, tire sensor, steering sensor, temperature sensor, humidity sensor, ultrasonic sensor, illuminance sensor, pedal position sensor, etc. can be included. The autonomous driving unit 140d is a technology that maintains a driving lane, a technology that automatically adjusts the speed such as adaptive cruise control, a technology that automatically travels along a predetermined route, and automatically sets a route when a destination is set. Technology, etc. can be implemented.

For example, the communication unit 110 may receive map data, traffic information data, and the like from an external server. The autonomous driving unit 140d may generate an autonomous driving route and a driving plan based on the acquired data. The controller 120 may control the driving unit 140a so that the vehicle or the autonomous vehicle 100 moves along the autonomous driving path according to the driving plan (eg, speed/direction adjustment). During autonomous driving, the communication unit 110 asynchronously/periodically acquires the latest traffic information data from an external server, and may acquire surrounding traffic information data from surrounding vehicles. In addition, during autonomous driving, the sensor unit 140c may acquire vehicle status and surrounding environment information. The autonomous driving unit 140d may update the autonomous driving route and the driving plan based on the newly acquired data/information. The communication unit 110 may transmit information about a vehicle location, an autonomous driving route, a driving plan, and the like to an external server. The external server may predict traffic information data in advance using AI technology or the like, based on information collected from the vehicle or autonomously driving vehicles, and may provide the predicted traffic information data to the vehicle or autonomously driving vehicles.

Although not limited thereto, various descriptions, functions, procedures, proposals, methods, and/or operational flow charts of the present invention disclosed in this document can be applied to various fields requiring wireless communication/connection (eg, 5G) between devices. have.

Hereinafter, it will be illustrated in more detail with reference to the drawings. In the following drawings/description, the same reference numerals may exemplify the same or corresponding hardware block, software block, or functional block, unless otherwise indicated.

5 illustrates a communication system 1 applied to the present invention.

Referring to FIG. 5, a communication system 1 applied to the present invention includes a wireless device, a base station, and a network. Here, the wireless device refers to a device that performs communication using a wireless access technology (eg, 5G NR (New RAT), LTE (Long Term Evolution)), and may be referred to as a communication/wireless/5G device. Although not limited thereto, wireless devices include robots 100a, vehicles 100b-1 and 100b-2, eXtended Reality (XR) devices 100c, hand-held devices 100d, and home appliances 100e. ), an Internet of Thing (IoT) device 100f, and an AI device/server 400. For example, the vehicle may include a vehicle equipped with a wireless communication function, an autonomous vehicle, a vehicle capable of performing inter-vehicle communication, and the like. Here, the vehicle may include an Unmanned Aerial Vehicle (UAV) (eg, a drone). XR devices include Augmented Reality (AR)/Virtual Reality (VR)/Mixed Reality (MR) devices, and include HMD (Head-Mounted Device), HUD (Head-Up Display), TV, smartphone It can be implemented in the form of a computer, a wearable device, a home appliance, a digital signage, a vehicle, a robot, and the like. Portable devices may include smart phones, smart pads, wearable devices (eg, smart watches, smart glasses), computers (eg, notebook computers, etc.). Home appliances may include TVs, refrigerators, washing machines, and the like. IoT devices may include sensors, smart meters, and the like. For example, the base station and the network may be implemented as a wireless device, and the specific wireless device 200a may operate as a base station/network node to other wireless devices.

The wireless devices 100a to 100f may be connected to the network 300 through the base station 200. AI (Artificial Intelligence) technology may be applied to the wireless devices 100a to 100f, and the wireless devices 100a to 100f may be connected to the AI server 400 through the network 300. The network 300 may be configured using a 3G network, a 4G (eg, LTE) network, or a 5G (eg, NR) network. The wireless devices 100a to 100f may communicate with each other through the base station 200/network 300, but may communicate directly (e.g. sidelink communication) without passing through the base station/network. For example, the vehicles 100b-1 and 100b-2 may perform direct communication (e.g. V2V (Vehicle to Vehicle)/V2X (Vehicle to Everything) communication). In addition, the IoT device (eg, sensor) may directly communicate with other IoT devices (eg, sensors) or other wireless devices 100a to 100f.

Wireless communication/connections 150a, 150b, and 150c may be established between the wireless devices 100a to 100f/base station 200, and the base station 200/base station 200. Here, wireless communication/connection includes various wireless access such as uplink/downlink communication 150a, sidelink communication 150b (or D2D communication), base station communication 150c (eg relay, Integrated Access Backhaul). This can be achieved through technology (eg 5G NR) Through wireless communication/connections 150a, 150b, 150c, the wireless device and the base station/wireless device, and the base station and the base station can transmit/receive radio signals to each other. For example, the wireless communication/connection 150a, 150b, 150c can transmit/receive signals through various physical channels. To this end, based on various proposals of the present invention, At least some of a process of setting various configuration information, various signal processing processes (eg, channel encoding/decoding, modulation/demodulation, resource mapping/demapping, etc.), resource allocation process, and the like may be performed.

DRX (Discontinuous Reception) operation

The UE may perform the DRX operation while performing the procedures and/or methods described/suggested above. A terminal in which DRX is configured can reduce power consumption by discontinuously receiving DL signals. DRX may be performed in Radio Resource Control (RRC)_IDLE state, RRC_INACTIVE state, and RRC_CONNECTED state. In the RRC_IDLE state and RRC_INACTIVE state, the DRX is used to receive paging signals discontinuously. Hereinafter, DRX performed in the RRC_CONNECTED state will be described (RRC_CONNECTED DRX).

6 illustrates the DRX cycle (RRC_CONNECTED state).

Referring to FIG. 6, the DRX cycle consists of On Duration and Opportunity for DRX. The DRX cycle defines a time interval in which On Duration is periodically repeated. On Duration represents a time period during which the UE monitors to receive the PDCCH. When DRX is configured, the UE performs PDCCH monitoring during On Duration. If there is a PDCCH successfully detected during PDCCH monitoring, the UE operates an inactivity timer and maintains an awake state. On the other hand, if there is no PDCCH successfully detected during PDCCH monitoring, the UE enters a sleep state after the On Duration ends. Accordingly, when DRX is configured, PDCCH monitoring/reception may be discontinuously performed in the time domain in performing the procedure and/or method described/proposed above. For example, when DRX is configured, in the present invention, a PDCCH reception opportunity (eg, a slot having a PDCCH search space) may be set discontinuously according to the DRX configuration. On the other hand, when DRX is not set, PDCCH monitoring/reception may be continuously performed in the time domain. For example, when DRX is not set, a PDCCH reception opportunity (eg, a slot having a PDCCH search space) may be continuously set in the present invention. Meanwhile, regardless of whether or not DRX is set, PDCCH monitoring may be limited in a time period set as a measurement gap.

Table 1 shows the process of the terminal related to the DRX (RRC_CONNECTED state). Referring to Table 1, DRX configuration information is received through higher layer (eg, RRC) signaling, and whether DRX ON/OFF is controlled by the DRX command of the MAC layer. When DRX is configured, the UE may perform PDCCH monitoring discontinuously in performing the procedure and/or method described/suggested in the present invention, as illustrated in FIG. 6.

Type of signals UE procedure 1 ^st step RRC signaling(MAC-
CellGroupConfig) -Receive DRX configuration information 2 ^nd Step MAC CE
((Long) DRX command MAC CE) -Receive DRX command 3 ^rd Step - -Monitor a PDCCH during an on-duration of a DRX cycle

Here, the MAC-CellGroupConfig includes configuration information required to set a medium access control (MAC) parameter for a cell group. MAC-CellGroupConfig may also include configuration information about DRX. For example, MAC-CellGroupConfig defines DRX and may include information as follows:-Value of drx-OnDurationTimer: Defines the length of the start section of the DRX cycle.

-Value of drx-InactivityTimer: Defines the length of the time interval in which the terminal is awake after the PDCCH opportunity in which the PDCCH indicating initial UL or DL data is detected

-Value of drx-HARQ-RTT-TimerDL: Defines the length of the maximum time interval from receiving the initial DL transmission until the DL retransmission is received.

-Value of drx-HARQ-RTT-TimerDL: After the grant for initial UL transmission is received, the length of the maximum time interval until the grant for UL retransmission is received is defined.

-drx-LongCycleStartOffset: Defines the time length and start point of the DRX cycle

-drx-ShortCycle (optional): Defines the time length of the short DRX cycle

Here, if any one of drx-OnDurationTimer, drx-InactivityTimer, drx-HARQ-RTT-TimerDL, and drx-HARQ-RTT-TimerDL is in operation, the UE performs PDCCH monitoring at every PDCCH opportunity while maintaining the awake state.

7 is a diagram illustrating physical channels used in a 3GPP system and a general signal transmission method using them.

When the terminal is powered on or newly enters a cell, the terminal performs an initial cell search operation such as synchronizing with the base station (S701). To this end, the UE receives a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) from the base station to synchronize with the base station and obtain information such as cell ID. Thereafter, the terminal may receive a physical broadcast channel (PBCH) from the base station to obtain intra-cell broadcast information. Meanwhile, the UE may receive a downlink reference signal (DL RS) in the initial cell search step to check the downlink channel state.

After completing the initial cell search, the UE acquires more detailed system information by receiving a Physical Downlink Control Channel (PDCCH) and a Physical Downlink Control Channel (PDSCH) according to the information carried on the PDCCH. It can be done (S702).

Meanwhile, when accessing the base station for the first time or when there is no radio resource for signal transmission, the terminal may perform a random access procedure (RACH) to the base station (S703 to S706). To this end, the UE transmits a specific sequence as a preamble through a physical random access channel (PRACH) (S703 and S705), and a response message to the preamble through a PDCCH and a corresponding PDSCH (RAR (Random Access Response) message) In the case of contention-based RACH, a contention resolution procedure may be additionally performed (S706).

After performing the above-described procedure, the UE receives PDCCH/PDSCH (S707) and physical uplink shared channel (PUSCH)/physical uplink control channel as a general uplink/downlink signal transmission procedure. Control Channel; PUCCH) transmission (S708) can be performed. In particular, the terminal may receive downlink control information (DCI) through the PDCCH. Here, the DCI includes control information such as resource allocation information for the terminal, and different formats may be applied according to the purpose of use.

On the other hand, the control information transmitted by the terminal to the base station through uplink or received by the base station by the terminal is a downlink/uplink ACK/NACK signal, a channel quality indicator (CQI), a precoding matrix index (PMI), a rank indicator (RI) ) And the like. The UE may transmit control information such as the above-described CQI/PMI/RI through PUSCH and/or PUCCH.

Meanwhile, the NR system is considering a method of using a high ultra-high frequency band, that is, a millimeter frequency band of 6 GHz or higher in order to transmit data while maintaining a high transmission rate to a large number of users using a wide frequency band. In 3GPP, this is used under the name NR, and in the present invention, it will be referred to as an NR system in the future.

NR supports multiple numerology (or subcarrier spacing (SCS)) to support various 5G services. For example, when the SCS is 15 kHz, it supports a wide area in traditional cellular bands, and when the SCS is 30 kHz/60 kHz, it is dense-urban, lower latency. And a wider carrier bandwidth, and when the SCS is 60 kHz or higher, a bandwidth greater than 24.25 kHz is supported to overcome phase noise.

The NR frequency band is defined as a frequency range of two types (FR1, FR2). FR1 is a sub 6GHz range, and FR2 may mean a millimeter wave (mmW) in the above 6GHz range.

Table 2 below shows the definition of the NR frequency band.

Frequency Range Designation Corresponding frequency range Subcarrier Spacing FR1 410MHz-7125MHz 15, 30, 60 kHz FR2 24250MHz-52600MHz 60, 120, 240 kHz

< Unlicensed band/shared spectrum system >

8 is a diagram illustrating an example of a wireless communication system supporting an unlicensed band to which various embodiments of the present disclosure are applicable.

In the following description, a cell operating in a licensed band (hereinafter, L-band) is defined as an L-cell, and a carrier of the L-cell is defined as a (DL/UL) LCC. In addition, a cell operating in an unlicensed band (hereinafter, U-band) is defined as a U-cell, and a carrier of the U-cell is defined as (DL/UL) UCC. The carrier/carrier-frequency of the cell may mean the operating frequency (eg, center frequency) of the cell. Cell/carrier (eg, CC) is collectively referred to as a cell.

When the terminal and the base station transmit and receive signals through the carrier-coupled LCC and UCC as shown in FIG.8(a), the LCC may be set to PCC (Primary CC) and the UCC may be set to SCC (Secondary CC).

As shown in FIG. 8(b), the terminal and the base station may transmit and receive signals through one UCC or a plurality of LCCs and UCCs combined with a carrier. That is, the terminal and the base station can transmit and receive signals through only UCC(s) without an LCC. Hereinafter, the signal transmission/reception operation in the unlicensed band described in various embodiments of the present disclosure may be performed based on all of the above-described deployment scenarios (unless otherwise noted).

1. Radio Frame Structure for Unlicensed Band

For operation in an unlicensed band, a frame structure type 3 or NR frame structure of LTE may be used. The configuration of OFDM symbols occupied for uplink/downlink signal transmission in the frame structure for the unlicensed band may be set by the base station. Here, the OFDM symbol may be replaced with an SC-FDM(A) symbol.

In order to transmit a downlink signal through an unlicensed band, the base station may inform the terminal of the configuration of OFDM symbols used in subframe #n through signaling. In the following description, a subframe may be replaced with a slot or a time unit (TU).

Specifically, in the case of a wireless communication system supporting an unlicensed band, the UE subframes through a specific field (e.g., Subframe configuration for LAA field, etc.) received from the base station in subframe #n-1 or subframe #n. It is possible to assume (or identify) the configuration of the OFDM symbol occupied in #n.

Table 3 shows the configuration of OFDM symbols used for transmission of a downlink physical channel and/or a physical signal in a current and/or next subframe in a subframe configuration for LAA field in a wireless communication system. Illustrate how to represent.

In order to transmit an uplink signal through an unlicensed band, the base station may inform the terminal of information on the uplink transmission period through signaling.

Specifically, in the case of an LTE system supporting an unlicensed band, the terminal may obtain'UL duration' and'UL offset' information for subframe #n through the'UL duration and offset' field in the detected DCI.

Table 4 illustrates how the UL duration and offset field indicates UL offset and UL duration configuration in a wireless communication system.

2. Channel access procedure general

The following definitions may be applied to terms used in the description of various embodiments of the present disclosure to be described later unless otherwise stated.

-A channel may mean a carrier or a part of a carrier composed of a contiguous set of RBs on which a channel access procedure is performed in a shared spectrum.

-The channel access procedure may be a sensing-based procedure for evaluating the availability of a channel for performing transmission. The basic unit of sensing may be a sensing slot having a duration of Tsl = 9 us. When the base station or the UE detects the channel during the sensing slot period and determines that the detected power detected for at least 4us in the sensing slot period is less than the energy detection threshold XThresh, the sensing slot period Tsl may be considered as idle. Otherwise, the sensing slot period Tsl may be considered busy.

-Channel occupancy may mean transmission in a channel by a base station/UE after performing a corresponding channel access procedure in this section.

-Channel occupancy time means that after the base station/UE performs the corresponding channel access procedure in this section, the base station/UE and any base station/UE(s) sharing channel occupancy transmit transmission on the channel. It can mean the total time performed. In order to determine the channel occupancy time, if the transmission gap is 25 us or less, the gap duration may be counted as the channel occupancy time. The channel occupancy time may be shared for transmission between the base station and the corresponding UE(s).

3. Downlink channel access procedure

The base station may perform the following downlink channel access procedure (CAP) for the unlicensed band in order to transmit a downlink signal in the unlicensed band.

3.1. Type 1 DL channel access procedures

This section describes a channel access procedure performed by a base station in which a time duration spanned by a sensing slot sensed idle before downlink transmission(s) is random. This clause is applicable to the following transmissions:

-Transmission(s) initiated by a base station including PDSCH/PDCCH/EPDCCH (Transmission(s) initiated by a base station including PDSCH/PDCCH/EPDCCH), or,

-Transmission(s) initiated by the base station, including a unicast PDSCH with user plane data, or a unicast PDSCH with user plane data and a unicast PDCCH for scheduling user plane data )(Transmission(s) initiated by a base station including unicast PDSCH with user plane data, or unicast PDSCH with user plane data and unicast PDCCH scheduling user plane data), or,

-Transmission(s) initiated by the base station with only discovery bursts, or with discovery bursts multiplexed with non-unicast information. Here, the transmission period may be greater than 1 ms, or the transmission may cause the discovery burst duty cycle to exceed 1/20.

The base station senses whether the channel is in an idle state during the sensing slot period of the delay period T _d , and after the counter N is 0 in step 4 below, the base station may transmit transmission. At this time, the counter N is adjusted by channel sensing for an additional sensing slot duration according to the following procedure:

1) Set N=N _init . Here, N _init is an arbitrary number of evenly distributed between _p is from 0 CW (random number uniformly distributed between 0 and CW p). Then go to step 4.

2) If N>0 and the base station chooses to decrement the counter, set N=N-1.

3) The channel for the additional sensing slot period is sensed. At this time, if the additional sensing slot period is idle, the process moves to step 4. If not, go to step 5.

4) If N=0, the procedure is stopped. Otherwise, go to step 2.

5) Add a delay interval T _d in the busy (busy), sensing slot is detected or sensed the channel until the further delay of all sensing slot interval T _d are detected as idle.

6) If the corresponding channel is sensed as idle during all sensing slot periods of the additional delay period T _{d, the process moves to step 4.} If not, go to step 5.

9 is a diagram illustrating a DL CAP for unlicensed band transmission to which various embodiments of the present disclosure are applicable.

A type 1 downlink channel access procedure for unlicensed band transmission to which various embodiments of the present disclosure are applicable may be summarized as follows.

For downlink transmission, a transmitting node (eg, a base station) may initiate a channel access procedure (CAP) (2010).

The base station may randomly select the backoff counter N within the contention window (CW) according to step 1. At this time, the value of N is set to the initial value Ninit (2020). Ninit is selected as an arbitrary value from 0 to CWp.

Subsequently, according to step 4, if the backoff counter value (N) is 0 (2030; Y), the base station ends the CAP process (2032). Subsequently, the base station may perform Tx burst transmission (2034). On the other hand, if the backoff counter value is not 0 (2030; N), the base station decreases the backoff counter value by 1 according to step 2 (2040).

Subsequently, the base station checks whether the channel is in an idle state (2050), and if the channel is in an idle state (2050; Y), it checks whether the backoff counter value is 0 (2030).

Conversely, in operation 2050, if the channel is not in an idle state, that is, if the channel is in a busy state (2050; N), the base station uses a delay period longer than the sensing slot time (eg, 9usec) according to step 5 (defer duration Td; 25usec). For above), it is checked whether the corresponding channel is in an idle state (2060). If the channel is idle in the delay period (2070; Y), the base station may resume the CAP process again.

For example, if the backoff counter value Ninit is 10 and the backoff counter value decreases to 5 and then it is determined that the channel is busy, the base station senses the channel during the delay period to determine whether it is in the idle state. At this time, if the channel is idle during the delay period, the base station does not set the backoff counter value Ninit, but can perform the CAP process again from the backoff counter value 5 (or from 4 after decreasing the backoff counter value by 1). have.

On the other hand, if the channel is in the busy state during the delay period (2070; N), the base station performs step 2060 again to check whether the channel is in the idle state during the new delay period.

In the above procedure, when the base station does not transmit transmission after step 4, the base station may transmit transmission on the channel if the following conditions are satisfied:

When the base station is prepared to transmit transmission and the corresponding channel is sensed as idle during at least the sensing slot period Tsl, and immediately before the transmission, the channel is sensed as idle during all sensing slot periods of the delay period Td. Occation

Conversely, when the base station senses the channel after being prepared to transmit transmission, the channel is not sensed as idle during the sensing slot period Tsl, or immediately before the intended transmission (immediately before) any one of the delay period Td. If the channel is not sensed as idle during the sensing slot period, the base station proceeds to step 1 after sensing that the channel is idle during the sensing slot period of the delay period Td (proceed to step 1).

The delay interval Td is composed of an interval Tf (=16us) immediately following mp consecutive sensing slot intervals. Here, each sensing slot period Tsl is 9us, and Tf includes an idle sensing slot period Tsl at the start point of Tf.

Table 5 illustrates that mp applied to the CAP, minimum CW, maximum CW, maximum channel occupancy time (MCOT), and allowed CW sizes vary according to the channel access priority class.

3.2. Type 2 DL channel access procedures

3.2.1. Type 2A DL channel access procedure

The base station may transmit transmission immediately after the corresponding channel is sensed as idle for at least the sensing period Tshort dl =25 us. Here, Tshort dl consists of a section Tf (=16us) immediately following one sensing slot section. Tf includes a sensing slot at the start point of Tf. When two sensing slots in the Tshort dl are sensed as idle, the channel is considered to be idle during the Tshort dl.

3.2.2. Type 2B DL channel access procedure

The base station may transmit transmission immediately after the corresponding channel is sensed as idle during Tf =16 us. Tf includes a sensing slot occurring within the last 9 us of Tf. When a channel is sensed to be in an idle state for at least 5us or more with sensing of at least 4us occurring in a sensing slot, the channel is considered to be idle during Tf.

3.2.3. Type 2C DL channel access procedure

If the base station follows the procedure of this section to transmit the transmission, the base station does not sense the channel before transmitting the transmission. The maximum duration corresponding to the transmission is 584us.

4. Channel access procedure for transmission(s) on multiple channels

The base station may access multiple channels on which transmission is performed through one of the following type A or type B procedures.

4.1. Type A multi-carrier access procedures

상 채널 접속을 수행한다. 여기서, C는 상기 기지국이 전송하고자 하는 (intend to transmit) 채널의 세트이고,

이고, q는 상기 기지국이 전송하고자 하는 채널의 개수이다.According to the procedure disclosed in this section, the base station

Phase channel connection is performed. Here, C is a set of channels intended to be transmitted by the base station,

And q is the number of channels to be transmitted by the base station.

별로 결정되고, 이 경우 각 채널 별 카운터는

라 표시한다. Counter N considered in CAP is for each channel

It is determined for each channel, and in this case, the counter for each channel is

Mark d.

4.1.1. Type A1 multi-channel access procedure

별로 결정되고, 각 채널 별 카운터는

라 표시한다. Counter N considered in CAP is for each channel

It is determined for each channel, and the counter for each channel is

Mark d.

상 전송을 중지(cease)한 경우, 만약 상기 채널을 공유하는 다른 기술의 부재가 긴 구간 동안 보증될 수 있다면 (예: 규정의 레벨에 의해) (if the absence of any other technology sharing the channel can be guaranteed on a long term basis (e.g., by level of regulation)), 각 채널 c _i (이때, c _i는 c _j와 상이함,

)을 위해,

의 구간을 기다린 이후 또는

를 재 초기화 (reinitialising) 한 이후 아이들 센싱 슬롯이 검출되면 상기 기지국은

감소를 재개(resume)할 수 있다.Any one channel of the base station

In the case of cease transmission, if the absence of any other technology sharing the channel can be guaranteed for a long period (e.g., by the level of regulation) (if the absence of any other technology sharing the channel can be guaranteed on a long term basis (eg, by level of regulation)), each channel c _i (where c _i is different from c _j,

)for,

After waiting for a section of or

When an idle sensing slot is detected after reinitializing, the base station

Decrease can be resumed.

4.1.2. Type A2 multi-channel access procedure

별 카운터 N은 앞서 상술한 내용들에 따라 결정될 수 있고, 이때 각 채널 별 카운터는

라 표시한다. 여기서,

는 가장 큰 CW _p 값을 갖는 채널을 의미할 수 있다. 각 채널

를 위해,

로 설정될 수 있다.Each channel

Star counter N may be determined according to the above-described contents, in which case the counter for each channel is

Mark d. here,

May mean a channel having the largest CW _{p value.} Each channel

for,

Can be set to

가 결정된 어느 하나의 채널에 대한 전송을 중단(cease)하는 경우, 상기 기지국은 모든 채널을 위한

를 재 초기화(reinitialise)한다.Base station

When ceases transmission for any one channel for which is determined, the base station is used for all channels.

Reinitialize.

4.2. Type B multi-channel access procedure

는 기지국에 의해 다음과 같이 선택될 수 있다.channel

May be selected by the base station as follows.

상 각각의 전송에 앞서 상기 C로부터 균등하게 임의적으로 (uniformly randomly)

를 선택하거나,-The base station is a multi-channel

Prior to transmission of each phase, uniformly randomly from C above

Or

를 선택하지 않는다.-The base station is more than once every 1 second

Do not choose.

이고, q는 상기 기지국이 전송하고자 하는 채널의 개수이다.Here, C is a set of channels intended to be transmitted by the base station,

And q is the number of channels to be transmitted by the base station.

상에서의 전송을 위해, 상기 기지국은 4.2.1. 절 또는 4.2.2. 절에 개시된 수정 사항 (medication)과 함께 3.1 절에 개시된 절차에 따라 채널

상의 채널 접속을 수행한다.channel

For transmission on the base station, the base station 4.2.1. Section or 4.2.2. Channels in accordance with the procedures set out in Section 3.1 together with the indications set out in Section 3.1.

Channel access on the server.

인 채널 중 채널

상에서의 전송을 위해,

In channel out of channel

For transmission on the top,

를 위해, 상기 기지국은 채널

상에서의 전송에 바로 앞서 (immediately before) 적어도 센싱 구간 (sensing interval)

동안 채널

를 센싱한다. 그리고, 상기 기지국은 적어도 센싱 구간

동안 채널

가 아이들임을 센싱한 바로 직후 (immediately after) 채널

상에서 전송을 수행할 수 있다. 주어진 구간

내 채널

상 아이들 센싱이 수행되는 모든 시간 구간 동안 상기 채널이 아이들로 센싱되는 경우, 상기 채널

는

를 위한 아이들로 고려될 수 있다.Each channel

For, the base station is a channel

Immediately before transmission on the image (sensing interval) at least

While channel

Is sensed. And, the base station is at least a sensing period

While channel

Immediately after sensing that the child is a child (immediately after) channel

Transfer can be performed on the. Given interval

My channel

When the channel is sensed as idle during all time periods in which phase idle sensing is performed, the channel

Is

Can be considered as children for.

(이때,

)상에서 상기 표 5의 T _mcot,p를 초과하는 구간을 위해 (for a period exceeding T _mcot,p) 전송을 수행하지 않는다. 여기서, T _mcot,p는 채널

을 위해 사용되는 채널 접속 파라미터를 사용하여 결정된다.The base station is a channel

(At this time,

_), (for a period exceeding T mcot,p) transmission is not performed _{for a period exceeding T mcot,p in} Table 5 above. Where T _mcot,p is the channel

It is determined using the channel access parameters used for.

In the procedure of this section, the channel frequency of the channel set C selected by the gNB is one subset of the predefined channel frequency sets.

4.2.1. Type B1 multi-channel access procedure

A single CW _p value is maintained for channel set C.

상 채널 접속을 위한 CW _p를 결정하기 위해, 앞서 3.1 절에서 상술한 절차의 스텝 2는 다음과 같이 수정된다.channel

_{In order to determine the CW p} for the phase channel access, Step 2 of the procedure described above in Section 3.1 is modified as follows.

의 참조 서브프레임 k 내 PDSCH 전송(들)에 대응하는 HARQ-ACK 값들의 적어도

가 NACK으로 결정되는 경우, 모든 우선순위 클래스

를 위한 CW _p를 다음 높은 허용된 값으로 (next higher allowed value)로 증가한다. 아닌 경우, 스텝 1로 이동한다.-All channels

At least of HARQ-ACK values corresponding to PDSCH transmission(s) in the reference subframe k of

Is determined as NACK, all priority classes

The CW _p for is increased to the next higher allowed value. If not, go to step 1.

4.2.2. Type B2 multi-channel access procedure

을 위해 독립적으로 유지된다. 채널

를 위한 CW _p 를 결정하기 위해, 채널

와 완전히 또는 부분적으로 겹치는 임의의 PDSCH 가 사용될 수 있다. 채널

을 위한 N _init을 결정하기 위해, 채널

의 CW _p 값이 사용된다. 여기서,

는 세트 C 내 모든 채널들 중 가장 큰 CW _p를 갖는 채널이다.CW _p value for each channel

Is maintained independently for the sake of channel

To _{determine the CW p} for the channel

Any PDSCH that completely or partially overlaps with may be used. channel

To _{determine the N init} for the channel

The CW _p value of is used. here,

Is the channel with the largest CW _{p among all channels in set C.}

5. Uplink channel access procedures

The UE and the base station scheduling or configuring UL transmission for the UE perform the following procedure for access to a channel (performing LAA S cell transmission(s)). In the following description, it is assumed that a P cell, which is a licensed band and an S cell, which is one or more unlicensed bands, are basically configured for a terminal and a base station, and an uplink CAP operation applicable to various embodiments of the present disclosure will be described in detail do. However, the uplink CAP operation may be equally applied even when only an unlicensed band is set for the terminal and the base station.

The UE may access a channel on which UL transmission(s) is performed according to a type 1 or type 2 UL channel access procedure.

Table 6 illustrates that mp applied to the CAP, minimum CW, maximum CW, maximum channel occupancy time (MCOT), and allowed CW sizes vary according to the channel access priority class.

5.1. Type 1 UL channel access procedure

This section describes a channel access procedure performed by a UE in which a time duration spanned by a sensing slot sensed idle before uplink transmission(s) is random. This clause is applicable to the following transmissions:

-Scheduled and/or configured PUSCH/SRS transmission(s) from the base station

-Scheduled and/or configured PUCCH transmission(s) from the base station

-Transmission(s) related to RAP (random access procedure)

10 is a diagram illustrating a UL CAP for transmission in an unlicensed band to which various embodiments of the present disclosure are applicable.

The type 1 UL CAP of the UE for unlicensed band transmission to which various embodiments of the present disclosure are applicable may be summarized as follows.

For uplink transmission, a transmitting node (eg, UE) may initiate a channel access procedure (CAP) to operate in an unlicensed band (2110).

The UE may randomly select the backoff counter N within the contention window (CW) according to step 1. At this time, the value of N is set to the initial value Ninit (2120). Ninit is selected as an arbitrary value from 0 to CWp.

Subsequently, according to step 4, if the backoff counter value (N) is 0 (2130; Y), the UE ends the CAP process (2132). Subsequently, the UE may perform Tx burst transmission (2134). On the other hand, if the backoff counter value is not 0 (2130; N), the UE decreases the backoff counter value by 1 according to step 2 (2140).

Subsequently, the UE checks whether the channel is in an idle state (2150), and if the channel is in an idle state (2150; Y), it checks whether the backoff counter value is 0 (2130).

Conversely, if the channel is not in an idle state in operation 2150, that is, if the channel is busy (2150; N), the UE has a delay period longer than the slot time (e.g., 9usec) according to step 5 (defer duration Td; 25usec or more) ), it is checked whether the corresponding channel is in an idle state (2160). If the channel is idle in the delay period (2170; Y), the UE may resume the CAP process again.

For example, if the backoff counter value Ninit is 10 and the backoff counter value decreases to 5 and then it is determined that the channel is busy, the UE senses the channel during the delay period to determine whether it is in the idle state. At this time, if the channel is idle during the delay period, the UE does not set the backoff counter value Ninit, but can perform the CAP process again from the backoff counter value 5 (or from 4 after decreasing the backoff counter value by 1). have.

On the other hand, if the channel is in the busy state during the delay period (2170; N), the UE performs operation 2160 again to check whether the channel is in the idle state during the new delay period.

In the above procedure, when the UE does not transmit UL transmission on a channel on which transmission(s) is performed after step 4 of the above-described procedure, the UE may transmit UL transmission on the channel if the following conditions are satisfied.

-When the UE is ready to perform transmission and the corresponding channel in at least the sensing slot period Tsl is sensed as idle, and

-When the channel is sensed as idle during all slot periods of the delay period Td immediately before the transmission (immediately before)

Conversely, if the channel is first sensed after the UE is ready to perform transmission, the channel in the sensing slot period Tsl is not sensed as idle, or any sensing slot period in the delay period Td immediately before the intended transmission. If the corresponding channel is not sensed as idle during the period, the UE proceeds to step 1 after the corresponding channel is sensed as idle during the slot periods of the delay period Td.

The delay interval Td is composed of an interval Tf (=16us) immediately following mp consecutive slot intervals. Here, each slot period Tsl is 9us, and Tf includes an idle slot period Tsl at the start point of Tf.

5.2. Type 2 UL channel access procedure

5.2.1 Type 2A UL channel connection procedure

동안 채널이 아이들임을 센싱한 바로 직후 (immediately after) 전송을 전송할 수 있다. T _{short_ul}은 하나의 센싱 슬롯 구간

바로 다음에 (immediately followed) 구간

로 구성된다. T _f는 상기 T _f의 시작 지점에 센싱 슬롯을 포함한다. 상기 T _{short_ul} 내 두 센싱 슬롯이 아이들로 센싱된 경우, 상기 채널은 T _{short_ul} 동안 아이들로 고려된다.If the UE is instructed to perform the type 2A UL channel access procedure, the UE uses the type 2A channel access procedure for UL transmission. The UE is at least a sensing period

The transmission can be transmitted immediately after sensing that the channel is idle. T _{short_ul} is one sensing slot section

Immediately following (immediately followed) section

It consists of. T _f includes a sensing slot at the start point of _{T f.} When two sensing slots in the T _{short_ul} are sensed as idle, the channel is considered as idle during _{T short_ul.}

5.2.2. Type 2B UL channel access procedure

If the UE is instructed to perform the type 2B UL channel access procedure, the UE uses the type 2B channel access procedure for UL transmission. The UE may transmit transmission immediately after the corresponding channel is sensed as idle during Tf =16 us. Tf includes a sensing slot occurring within the last 9 us of Tf. When a channel is sensed to be in an idle state for at least 5us or more with sensing of at least 4us occurring in a sensing slot, the channel is considered to be idle during Tf.

5.2.3. Type 2C UL channel access procedure

If the UE is instructed to perform the Type 2C UL channel access procedure, the UE does not sense the channel before transmitting the transmission in order to transmit the transmission. The maximum duration corresponding to the transmission is 584us.

6. Channel access procedure for UL multi-channel transmission(s)

If the UE:

-Scheduled to transmit on the set of channels C, if The UL scheduling grant for UL transmission on the channel set C indicates a type 1 channel access procedure, and UL transmissions are scheduled to start transmission at the same time for all channels in the channel set C, and/or

-It is an intention to perform uplink transmission on resources set on channel set C using a type 1 channel access procedure, and

If the channel frequencies of channel set C are a subset of one of the preset channel frequency sets:

상에서 전송을 수행할 수 있다.-The UE uses a type 2 channel access procedure

Transfer can be performed on the.

상 (여기서,

) UE 전송의 바로 직전에 (immediately before) 채널

상에서 타입 2 채널 접속 절차가 수행된 경우, 그리고--If channel

Phase (here,

) Immediately before UE transmission (immediately before) channel

When the type 2 channel access procedure is performed on the server, and

에 접속하고 있는 경우 (the UE has accessed channel

using Type 1 channel access procedure),--If the UE uses a type 1 channel access procedure,

(The UE has accessed channel

using Type 1 channel access procedure),

는 UE에 의해 채널 세트 C로부터 균등하게 임의적으로 (uniformly randomly) 선택된다.---A channel prior to performing a type 1 channel access procedure on any (any) channel in channel set C.

Is uniformly randomly selected from channel set C by the UE.

에서 전송하지 않을 수 있다.-If the UE cannot access any one channel, the UE is a channel within the bandwidth of the carrier of the scheduled or carrier bandwidth set by UL resources.

May not be transmitted from.

11 illustrates an SSB structure. The terminal may perform cell search, system information acquisition, beam alignment for initial access, and DL measurement based on the SSB. SSB is used interchangeably with a Synchronization Signal/Physical Broadcast Channel (SS/PBCH) block.

Referring to FIG. 11, the SSB is composed of PSS, SSS and PBCH. The SSB is composed of 4 consecutive OFDM symbols, and PSS, PBCH, SSS/PBCH and PBCH are transmitted for each OFDM symbol. The PSS and SSS are each composed of 1 OFDM symbol and 127 subcarriers, and the PBCH is composed of 3 OFDM symbols and 576 subcarriers. Polar coding and Quadrature Phase Shift Keying (QPSK) are applied to the PBCH. The PBCH consists of a data RE and a demodulation reference signal (DMRS) RE for each OFDM symbol. There are 3 DMRS REs for each RB, and 3 data REs exist between the DMRS REs.

Cell search

Cell search refers to a process in which a UE acquires time/frequency synchronization of a cell and detects a cell identifier (eg, Physical layer Cell ID, PCID) of the cell. PSS is used to detect a cell ID within a cell ID group, and SSS is used to detect a cell ID group. PBCH is used for SSB (time) index detection and half-frame detection.

The cell search process of the terminal may be summarized as shown in Table 7 below.

Type of Signals Operations 1 ^st step PSS * SS/PBCH block (SSB) symbol timing acquisition
* Cell ID detection within a cell ID group
(3 hypothesis) 2 ^nd Step SSS * Cell ID group detection (336 hypothesis) 3 ^rd Step PBCH DMRS * SSB index and Half frame (HF) index(Slot and frame boundary detection) 4 ^th Step PBCH * Time information (80 ms, System Frame Number (SFN), SSB index, HF) * Remaining Minimum System Information (RMSI) Control resource set (CORESET)/Search space configuration 5 ^th Step PDCCH and PDSCH * Cell access information* RACH configuration

12 illustrates SSB transmission.

SSB is transmitted periodically according to the SSB period. The SSB basic period assumed by the terminal during initial cell search is defined as 20 ms. After cell access, the SSB period may be set to one of {5ms, 10ms, 20ms, 40ms, 80ms, 160ms} by a network (eg, a base station). At the beginning of the SSB period, a set of SSB bursts is constructed. The SSB burst set consists of a 5 ms time window (ie, half-frame), and the SSB can be transmitted up to L times within the SS burst set. The maximum number of transmissions L of the SSB may be given as follows according to the frequency band of the carrier. One slot contains a maximum of two SSBs.

-For frequency range up to 3 GHz, L = 4

-For frequency range from 3GHz to 6 GHz, L = 8

-For frequency range from 6 GHz to 52.6 GHz, L = 64

The temporal position of the SSB candidate in the SS burst set may be defined as follows according to the SCS. The temporal position of the SSB candidate is indexed from 0 to L-1 in the temporal order within the SSB burst set (ie, half-frame) (SSB index).

-Case A-15 kHz SCS: The index of the start symbol of the candidate SSB is given as {2, 8} + 14*n. When the carrier frequency is 3 GHz or less, n=0, 1. When the carrier frequency is 3 GHz to 6 GHz, n = 0, 1, 2, 3.

-Case B-30 kHz SCS: The index of the start symbol of the candidate SSB is given as {4, 8, 16, 20} + 28*n. When the carrier frequency is 3 GHz or less, n=0. When the carrier frequency is 3 GHz to 6 GHz, n=0, 1.

-Case C-30 kHz SCS: The index of the start symbol of the candidate SSB is given as {2, 8} + 14*n. When the carrier frequency is 3 GHz or less, n=0, 1. When the carrier frequency is 3 GHz to 6 GHz, n = 0, 1, 2, 3.

-Case D-120 kHz SCS: The index of the start symbol of the candidate SSB is given as {4, 8, 16, 20} + 28*n. When the carrier frequency is greater than 6 GHz, n=0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18.

-Case E-240 kHz SCS: The index of the start symbol of the candidate SSB is given as {8, 12, 16, 20, 32, 36, 40, 44} + 56*n. When the carrier frequency is greater than 6 GHz, n = 0, 1, 2, 3, 5, 6, 7, 8.

13 illustrates that the terminal obtains information on DL time synchronization.

The UE can acquire DL synchronization by detecting the SSB. The terminal may identify the structure of the SSB burst set based on the detected SSB index, and accordingly, may detect a symbol/slot/half-frame boundary. The number of the frame/half-frame to which the detected SSB belongs can be identified using SFN information and half-frame indication information.

Specifically, the UE may obtain 10-bit SFN (System Frame Number) information from the PBCH (s0 to s9). Of the 10-bit SFN information, 6 bits are obtained from MIB (Master Information Block), and the remaining 4 bits are obtained from PBCH TB (Transport Block).

Next, the terminal may acquire 1-bit half-frame indication information (c0). When the carrier frequency is 3 GHz or less, the half-frame indication information may be implicitly signaled using PBCH DMRS. PBCH DMRS indicates 3-bit information by using one of 8 PBCH DMRS sequences. Therefore, in the case of L=4, out of 3 bits that can be indicated using 8 PBCH DMRS sequences, the SSB index is indicated, and the remaining 1 bit may be used for half-frame indication purposes.

Finally, the UE may obtain an SSB index based on the DMRS sequence and PBCH payload. SSB candidates are indexed from 0 to L-1 in time order within the SSB burst set (ie, half-frame). When L = 8 or 64, the LSB (Least Significant Bit) 3 bits of the SSB index may be indicated using 8 different PBCH DMRS sequences (b0 to b2). When L = 64, 3 bits of the MSB (Most Significant Bit) of the SSB index are indicated through the PBCH (b3 to b5). When L = 2, the LSB 2 bits of the SSB index may be indicated using four different PBCH DMRS sequences (b0, b1). When L = 4, out of 3 bits that can be indicated using 8 PBCH DMRS sequences, the SSB index is indicated and the remaining 1 bit may be used for half-frame indication (b2).

System information acquisition

14 illustrates a system information (SI) acquisition process. The UE may acquire AS-/NAS-information through the SI acquisition process. The SI acquisition process may be applied to a UE in an RRC_IDLE state, an RRC_INACTIVE state, and an RRC_CONNECTED state.

SI is divided into MIB (Master Information Block) and a plurality of SIB (System Information Block). The MIB and the plurality of SIBs may be further divided into a minimum SI (SI) and another SI (other SI). Here, the minimum SI may be composed of MIB and SIB 1, and includes information for obtaining an SI different from basic information required for initial access. Here, SIB 1 may be referred to as RMSI (Remaining Minimum System Information). For details, refer to the following.

-The MIB includes information/parameters related to SIB1 (SystemInformationBlockType1) reception and is transmitted through the PBCH of the SSB. Upon initial cell selection, the UE assumes that the half-frame with SSB is repeated in a 20ms cycle. The UE may check whether there is a CORESET (Control Resource Set) for the Type0-PDCCH common search space based on the MIB. The Type0-PDCCH common search space is a kind of PDCCH search space, and is used to transmit a PDCCH for scheduling SI messages. If there is a Type0-PDCCH common search space, the UE based on the information in the MIB (e.g., pdcch-ConfigSIB1) (i) a plurality of consecutive RBs constituting CORESET and one or more consecutive symbols and (ii) PDCCH opportunity (Ie, a time domain location for PDCCH reception) can be determined. When the Type0-PDCCH common search space does not exist, pdcch-ConfigSIB1 provides information on a frequency location in which SSB/SIB1 exists and a frequency range in which SSB/SIB1 does not exist.

-SIB1 includes information related to availability and scheduling (eg, transmission period, SI-window size) of the remaining SIBs (hereinafter, SIBx, x is an integer greater than or equal to 2). For example, SIB1 may inform whether SIBx is periodically broadcast or is provided at a request of a terminal through an on-demand method. When SIBx is provided by an on-demand method, SIB1 may include information necessary for the UE to perform an SI request. SIB1 is transmitted through a PDSCH, a PDCCH scheduling SIB1 is transmitted through a Type0-PDCCH common search space, and SIB1 is transmitted through a PDSCH indicated by the PDCCH.

-SIBx is included in the SI message and transmitted through the PDSCH. Each SI message is transmitted within a periodic time window (ie, SI-window).

Beam alignment

15 illustrates multi-beam transmission of SSB.

Beam sweeping means that a transmission reception point (TRP) (eg, a base station/cell) changes a beam (direction) of a radio signal according to time (hereinafter, a beam and a beam direction may be mixed). SSB may be periodically transmitted using beam sweeping. In this case, the SSB index is implicitly linked with the SSB beam. The SSB beam may be changed in units of SSB (index) or may be changed in units of SSB (index) groups. In the latter case, the SSB beam remains the same within the SSB (index) group. That is, the transmission beam echo of the SSB is repeated in a plurality of consecutive SSBs. The maximum number of transmissions L of the SSB in the SSB burst set has a value of 4, 8 or 64 depending on the frequency band to which the carrier belongs. Accordingly, the maximum number of SSB beams in the SSB burst set may also be given as follows according to the frequency band of the carrier.

-For frequency range up to 3 GHz, Max number of beams = 4

-For frequency range from 3GHz to 6 GHz, Max number of beams = 8

-For frequency range from 6 GHz to 52.6 GHz, Max number of beams = 64

* When multi-beam transmission is not applied, the number of SSB beams is 1.

When the terminal attempts to initially access the base station, the terminal may align the base station and the beam based on the SSB. For example, after performing SSB detection, the terminal identifies the best SSB. Thereafter, the terminal may transmit the RACH preamble to the base station by using the PRACH resource linked/corresponding to the index (ie, the beam) of the best SSB. The SSB can be used to align the beam between the base station and the terminal even after initial access.

Channel measurement and rate-matching

16 illustrates a method of informing an actually transmitted SSB (SSB_tx).

In the SSB burst set, a maximum of L SSBs may be transmitted, and the number/locations at which SSBs are actually transmitted may vary for each base station/cell. The number/locations at which SSBs are actually transmitted is used for rate-matching and measurement, and information on the actually transmitted SSBs is indicated as follows.

-In case of rate-matching: It may be indicated through UE-specific RRC signaling or RMSI. The UE-specific RRC signaling includes a full (eg, length L) bitmap in both the below 6GHz and above 6GHz frequency ranges. On the other hand, RMSI includes a full bitmap at below 6GHz, and includes a compressed bitmap at above 6GHz. Specifically, information on the actually transmitted SSB may be indicated using a group-bit map (8 bits) + an intra-group bit map (8 bits). Here, a resource (eg, RE) indicated through UE-specific RRC signaling or RMSI is reserved for SSB transmission, and PDSCH/PUSCH may be rate-matched in consideration of SSB resources.

-In case of measurement: When in the RRC connected mode, the network (eg, the base station) may indicate the SSB set to be measured within the measurement interval. The SSB set may be indicated for each frequency layer. If there is no indication regarding the SSB set, the default SSB set is used. The default SSB set includes all SSBs in the measurement interval. The SSB set may be indicated using a full (eg, length L) bitmap of RRC signaling. When in RRC idle mode, the default SSB set is used.

In the LTE and/or NR system, the UE may perform UL transmission through a random access procedure (RACH Procedure) without being scheduled for direct uplink (UL) transmission from a given base station or cell. From the terminal point of view, the random access process in LTE and/or the system includes: 1) transmission of a random access preamble, 2) reception of a message (Msg) 2 corresponding to a random access response (RAR) , 3) Transmission of Msg 3 including Physical Uplink Shared Channel (PUSCH), 4) 4-step of reception of Msg 4 including information on contention resolution ) Procedure.

Here, Msg 2 is a message in which the base station receiving a preamble allocates UL resources to be used when the terminal transmitting the preamble transmits Msg 3. Through Msg 3, the terminal provides a connection request along with its own identification information such as an International Mobile Subscriber Identity (IMSI) or a Temporary Mobile Subscriber Identity (TMSI). Information can be transmitted. The base station receiving Msg 3 transmits identification information of the corresponding terminal and information necessary for random access through Msg 4, thereby preventing collisions that may occur between different terminals during the random access process, and performing a random access procedure for the corresponding terminal. You can complete it.

Unlike the conventional RACH procedure in LTE and NR Rel-15 that was configured in 4-step as described above, in NR Rel-16, processing delay by 4-step is simplified and small cell Alternatively, a study on a 2-step RACH procedure is in progress so that the RACH procedure can be utilized even in an unlicensed bandwidth. In the 2-step RACH, including the step of transmitting Message 3 (Msg 3) including a Physical Uplink Shared Channel (PUSCH) in the existing 4-step RACH and a contention resolution message, etc. The step of transmitting Msg 4 has been omitted. Instead, in the first step of the random access procedure, the UE transmits a message corresponding to Msg 3 together with a preamble to the base station as Msg A, and in response to Msg A, the base station sends a message corresponding to Msg 4 together with RAR as Msg B. Send it to the terminal. The terminal receiving Msg B completes the random access procedure by decoding Msg B and then performs data transmission/reception.

17 is a diagram showing a basic process of a 2-step RACH. Referring to FIG. 17, the terminal may receive 2-step RACH-related configuration information included in system information broadcasted from the base station (S1701). Upon receiving the 2-step RACH-related configuration information, the UE transmits the RACH preamble (or PRACH preamble) and Msg A including the PUSCH based on the configuration information in order to perform a random access procedure for the base station (S1703). In this case, the RACH preamble and PUSCH may be transmitted at regular intervals or successively transmitted in a time domain, and the corresponding PUSCH includes information about an identifier (ID) of the terminal. The base station is able to predict and receive a PUSCH or a continuous PUSCH having a corresponding gap by detecting a preamble. The base station receives an access request and/or response from an upper layer based on the ID information of the terminal transmitted through the PUSCH, and then sends Msg B including information such as RAR and contention resolution to the terminal as a response to Msg A. It is transmitted (S1705). Thereafter, depending on whether the terminal receives Msg B, the terminal can complete access to the base station and transmit and receive data with the base station in the same or similar manner as after the operation of receiving Msg 4 in the existing 4-step RACH procedure.

In the present disclosure below, various embodiments applicable in a 2-step RACH procedure are reviewed, and in particular, 1) a method of setting Msg A transmission power according to a Listen Before Talk (LBT) being performed in an unlicensed band, and 2) Msg B. A method of configuring PUCCH resources for HARQ-ACK transmission of the terminal as a response to the terminal can be looked at in detail.

2-step RACH procedure according to LBT in unlicensed band

In NR, since the UE can perform the random access procedure in the unlicensed band, the Listen Before Talk (LBT) process required for signal transmission and reception in the unlicensed band can be applied to signal transmission and reception for the random access procedure. That is, in the NR-Unlicensed spectrum (NR-U) system, LBT is always performed to check the idle or busy state of the transmission/reception channel before the base station and the terminal transmit and receive signals, which is a 2-step RACH procedure in the unlicensed band. The same may be performed in the procedure for transmitting and receiving Msg A and Msg B for.

Since the transmission of Msg A in the 2-step RACH procedure includes the transmission of the Msg A PUSCH along with the transmission of the Msg A PRACH preamble, it is performed later depending on the success or failure of the LBT for the Msg A PRACH preamble and Msg A PUSCH. Random access procedure can be changed. For example, if the UE successfully performs LBT before transmission of Msg A PRACH preamble and Msg A PUSCH and transmits to Msg A PUSCH without any problem, the base station correctly receives both Msg A PRACH preamble and Msg A PUSCH to resolve contention. Msg B including information can be transmitted to the terminal and the 2-step RACH procedure can be completed. Conversely, if the UE fails to LBT for Msg A PRACH preamble or Msg A PUSCH, the UE cannot successfully transmit Msg A, and the base station that does not receive Msg A instructs retransmission for Msg A or 4-step RACH procedure You can instruct a fall-back to a low.

At this time, whether Msg A is retransmitted due to LBT failure is a time gap between the transmission times of Msg A PRACH preamble and Msg A PUSCH, considering that Msg A includes both Msg A PRACH preamble and Msg A PUSCH. ) Can be treated differently. That is, whether the terminal continuously transmits the Msg A PUSCH after transmitting the Msg A PRACH preamble, or there is a time interval greater than the minimum time required for the LBT before transmitting the Msg A PUSCH after the terminal transmits the Msg A PRACH preamble. The retransmission procedure of Msg A may vary depending on whether it is in a situation.

(1) When Msg A PRACH preamble and Msg A PUSCH are continuously transmitted

When Msg A PRACH preamble and Msg A PUSCH are continuously transmitted, Msg A PRACH preamble and Msg A PUSCH are continuously transmitted in a single slot, or Msg A PRACH preamble and Msg A PUSCH associated therewith are transmitted in a single slot. It may mean the case of being transmitted.

That is, the case in which the Msg A PRACH preamble and the Msg A PUSCH are continuously transmitted includes a case where there is no time interval as long as the minimum time required for the LBT between the transmission of the Msg A PRACH preamble and the Msg A PUSCH, and FIG. 18 A situation like this can be an example.

FIG. 18 is a diagram illustrating an embodiment of transmission of Msg A according to whether a terminal succeeds or fails in an LBT and a configuration of a transmission beam direction. Fig. 18(A) shows that the UE succeeds in LBT at a specific time and continuously transmits Msg A PRACH preamble and Msg A PUSCH, and Fig. 18(B) shows that after the UE fails LBT at a certain time, the This indicates that the LBT at the next time point is successful and the Msg A PRACH preamble and the Msg A PUSCH are continuously transmitted. In both Figures 18 (A) and 18 (B), since the time interval equal to the condition time required for LBT does not exist between the transmission time points of Msg A PRACH preamble and Msg A PUSCH, the terminal LBT only before transmission of the Msg A PRACH preamble. When the Msg A PUSCH is transmitted, continuous transmission is performed as it is without performing the LBT. Therefore, in this case, according to the success or failure of the LBT performed prior to transmission of the Msg A PRACH preamble, the signal transmission operation of the terminal and the base station and power control for signal transmission may be set differently.

If the UE fails in LBT for Msg A PRACH preamble transmission at a certain point in time, the UE may perform LBT for Msg A PRACH preamble transmission again for the next RACH Occasion (RO) after the Association period from the time when the LBT fails. Or, if the terminal fails in LBT for Msg A PRACH preamble transmission at a certain point in time, the terminal starts a random access resource selection procedure anew, and the synchronization signal and physical broadcast channel (SSB; SS/PBCH) or SSB selection is performed based on the Reference Signal Received Power (RSRP) of CSI-RS (Channel State Information-Reference Signal), and the RO associated with SSB and RAPID (Random Access Preamble Index) are selected and the corresponding RO Msg A PRACH preamble can be transmitted, and Msg A PUSCH can also be continuously transmitted. In addition, since the state of the transmission channel continuously transmitted at this time is different from the previous transmission environment, the information (contents) and the modulation order included in the Msg A PUSCH according to the channel environment in which the Msg A PUSCH is transmitted. ) May be set differently from the previous Msg A PUSCH transmission. For example, when the channel state at the time of transmission of the Msg A PUSCH is good, the UE may transmit the Msg A PUSCH with a larger amount of information included, and a high demodulation order may be applied.

Here, in the case of Msg A, since Msg A PUSCH is transmitted after Msg A PRACH preamble is transmitted and before feedback from the base station, the maximum number of transmissions for Msg A retransmission, ramping step size, power ramping counter, etc. Transmission factors need to be set separately, and among them, specific methods to be described later may be considered for setting the power ramping counter and the maximum number of transmissions of Msg A.

First, in the case of the power ramping counter, since Msg A PRACH preamble and Msg A PUSCH are continuously transmitted, it may be appropriate to use a common power ramping counter for Msg A PRACH preamble and Msg A PUSCH. If the UE fails to transmit the Msg A PRACH preamble in the RO determined according to the LBT, the UE may transmit the Msg A PRACH preamble after LBT success by re-performing the LBT in the next RO as shown in FIG. 18(B). At this time, for the transmission of the Msg A PRACH preamble when the LBT is re-performed and the LBT is successful, the UE maintains or increases the power value compared to the power ramping counter that was attempted to transmit the Msg A PRACH preamble when the previous LBT fails. You can set the ramping counter. Here, the power ramping counter referred to in the present disclosure may mean a power ramping counter used for general retransmission.

1) How to set the transmit power by keeping the ramping counter at the same value as before

The terminal may first maintain the value of the power ramping counter as it is. That is, if the terminal performs LBT on the next RO due to LBT failure on the previous RO and transmits Msg A after success, it means that Msg A itself was not transmitted from the previous RO from the terminal point of view. Increasingly increasing the transmission power of the terminal may cause inefficient power waste. Eventually, the terminal may transmit Msg A by maintaining the originally intended transmission power by maintaining the value of the power ramping counter as it is.

2) How to set the transmit power by configuring the ramping counter to an increased value than before

The terminal may determine the transmission power by increasing the value of the power ramping counter. Although the UE transmits Msg A after success by performing the LBT for the next RO due to the LBT failure for the previous RO, the power ramping counter can be set by increasing the existing value by +1 to determine the transmission power. Determining the transmission power of Msg A by applying the power ramping counter increased by +1 means that other terminals that have tried the same RACH at the time of the previous RO will ramp the power at the time of the next RO to attempt RACH with the increased transmission power. In consideration of the fact that the transmission power is relatively small, it is possible to prevent the problem that the Msg A PRACH preamble of the terminal may be difficult to detect. In addition, the purpose of introducing the 2-step RACH procedure is to further reduce the latency caused by the 4-step RACH procedure, so that the terminal can access the network faster as the latency due to LBT in NR-U is delayed. Unlike the 4-step RACH procedure, it is possible to slightly reduce latency by increasing the detection probability by consuming additional power for each retransmission. For these reasons, if the UE transmits Msg A from the next RO due to the LBT failure for the previous RO, the LBT failure for the previous RO is regarded as Msg A transmission failure, and the power ramping counter is increased by +1 to Msg. It can be applied to transmission of A PRACH preamble and Msg A PUSCH.

3) How to set the transmission power by maintaining or increasing the power ramping counter according to the transmission beam direction

In consideration of the advantages and disadvantages of the above methods 1) and 2), the terminal may use a method of maintaining or increasing the power ramping counter according to the transmission beam direction. In other words, unlike the method of 1) that maintains power regardless of the beam direction and the method of 2) that increases the power regardless of the beam direction, in this method, the terminal determines the LBT failure for the previous RO as retransmission, but the terminal This is a method of increasing or maintaining the power ramping counter according to the transmission beam of.

19 is a diagram illustrating an embodiment of the present disclosure in which a power ramping counter is maintained or increased according to a transmission beam direction of a terminal. As shown in FIG. 19(A), when the transmission (Tx) spatial beam configured when the LBT for the previous RO fails and the transmission spatial beam configured when the LBT for the next RO is successful are different from each other, the UE Msg A can be transmitted by maintaining the power ramping counter of the same value as before. On the contrary, as shown in FIG. 19(B), when the transmission spatial beam configured when the LBT for the previous RO fails and the transmission spatial beam configured when the LBT for the next RO is successful are the same, the terminal increases the power ramping counter compared to the previous one. So that Msg A can be transmitted.

In summary, if the UE does not receive an indication that the LBT for the transmission or retransmission of the corresponding Msg A has failed in the transmission or retransmission of Msg A, the UE determines whether the transmission or retransmission of the last Msg A and the transmission spatial beam direction are the same. Accordingly, the transmit power is set by maintaining or increasing the power ramping counter. At this time, since the transmission spatial beam direction for transmission or retransmission of Msg A will be associated with the SSB selected by the terminal for transmission or retransmission of Msg A, the terminal may have the SSB selected for transmission or retransmission of Msg A past Msg. Depending on whether it is the same as the SSB selected for transmission or retransmission of A, it can be interpreted as setting the transmission power by maintaining or increasing the power ramping counter. In addition, here, considering that Msg A PRACH and Msg A PUSCH are continuously transmitted, the transmission spatial beam direction for transmission or retransmission of the last Msg A includes a transmission spatial beam direction configured for transmission or retransmission of the last PRACH. It can be understood as a concept of doing.

For example, when the UE transmits or retransmits Msg A, if the UE does not receive an indication from the lower layer that the LBT for the transmission or retransmission of the Msg A has failed, the UE transmits or retransmits the PRACH past its SSB. If it is not changed compared to the selected SSB, Msg A can be transmitted by setting the transmission power by increasing the power ramping counter by 1 compared to the previous one. Or, for example, when the UE transmits or retransmits Msg A, if the UE does not receive an indication from the lower layer that the LBT for the transmission or retransmission of the Msg A has failed, the UE transmits or retransmits the PRACH that the SSB selected by itself has passed. If it is changed compared to the SSB selected for, Msg A can be transmitted by setting the transmission power by maintaining the power ramping counter at the same value as before.

If the terminal receives an indication that the LBT for the transmission or retransmission of the Msg A has failed when transmitting or retransmitting Msg A, the terminal determines the LBT failure as retransmission and performs retransmission. If an indication for LBT failure recovery is configured, the UE may perform a random access resource selection procedure for a 2-step RACH procedure.

4) How to set the transmission power by maintaining or increasing the power ramping counter according to the relationship between the RO of the 2-step RACH procedure and the 4-step RACH procedure.

The UE may increase or maintain the power ramping counter according to the relationship between the RO of the 2-step RACH procedure and the 4-step RACH procedure. That is, the ramping counter may be increased or maintained depending on whether the RO for the 2-step RACH procedure and the RO for the 4-step RACH procedure are shared with each other or are set separately from each other.

The RO of the 2-step RACH procedure and the 4-step RACH procedure can be basically shared, and that the RO is shared means that the Msg 1 preamble in the 4-step RACH procedure and the Msg A PRACH preamble in the 2-step RACH procedure are It means that it is transmitted from the same RO. In addition, that the RO is set separately from each other means that the time/frequency resource for the Msg 1 preamble in the 4-step RACH procedure and the time/frequency resource for the Msg A PRACH preamble in the 2-step RACH procedure are It means to exist independently of each other.

If the above-described methods 1) to 3) deal with the operation of the terminal and the base station regardless of whether the RO is shared or set separately from each other, the method is used to determine whether the RO is shared or set separately from each other. Another power ramping counter determination method is applied. That is, when the RO for the 2-step RACH procedure and the RO for the 4-step RACH procedure are set separately from each other, the terminal performing the 2-step RACH procedure is The LBT failure at is recognized as a transmission/reception failure, and the value of the power ramping counter is increased for retransmission. On the other hand, if the RO for the 2-step RACH procedure and the RO for the 4-step RACH procedure are shared with each other, the UE can perform the 4-step RACH of the existing NR-U without distinction between the 2-step RACH procedure or the 4-step RACH procedure. As in the procedure, the value of the power ramping counter is maintained as in the previous 1) method.

On the other hand, the maximum number of transmissions of Msg A in the 2-step RACH procedure can be given separately from the 4-step RACH procedure, and if there is no value given separately, the maximum number of transmissions set for Msg 1 of the 4-step RACH procedure should be followed. can do. If the value of the power ramping counter is set to be greater than the maximum number of transmissions of Msg A by 1, the terminal may proceed with the reestablishment procedure according to Radio Link Failure (RLF). In addition, when the RO for the 2-step RACH procedure and the RO for the 4-step RACH procedure are shared with each other, the maximum number of transmissions of Msg 1 for the 4-step RACH procedure is the maximum number of Msg A in the 2-step RACH procedure. If it is set to be greater than the number of transmissions, the terminal may transmit only Msg 1 from when the power ramping counter is greater than the maximum number of transmissions of Msg A by 1. In addition, the value of the ramping step size may determine the transmission power for retransmission by applying the ramping step size for Msg 1 from a time when the power ramping counter becomes larger than the maximum number of transmissions of Msg A by 1. At this time, the UE's fall-back and RLF operations for the value and maximum value of each counter may be applicable to NR as well as NR-U.

(2) When there is a time interval between transmission of Msg A PRACH preamble and Msg A PUSCH

In this case, it means that after the UE transmits the Msg A PRACH preamble, there is a time interval greater than the minimum time required for the LBT before transmitting the Msg A PUSCH, and the transmission of the Msg A PRACH preamble and Msg A PUSCH is at a constant interval. Since the terminal is performed discontinuously, the UE performs LBT for both transmission of the Msg A PRACH preamble and the transmission of the Msg A PUSCH. Therefore, the operation of the terminal and the base station may differ differently depending on whether the LBT for the transmission time of each signal succeeds or fails. In addition, since there is a distance between transmission points of each signal, the beam direction determined according to the channel state may also vary, and thus power setting for retransmission may also be complicated. Hereinafter, the operation of the terminal and the base station according to the failure time of the LBT for the transmission of the Msg A PRACH preamble and Msg A PUSCH and the transmission power setting will be described.

The configuration of the power ramping counter in the above case is that, since Msg A PRACH preamble and Msg A PUSCH are transmitted at regular intervals, the power ramping counter is shared and used in relation to the retransmission power setting of Msg A PRACH preamble and Msg A PUSCH. A single counter, or dual counters used by configuring each power ramping counter for the retransmission power setting of Msg A PRACH preamble and Msg A PUSCH can be considered. Also, the maximum number of transmissions of Msg A is not commonly applied to the Msg A PRACH preamble and Msg A PUSCH, but the maximum number of transmissions for each of the Msg A PRACH preamble and Msg A PUSCH may be set.

In this case, when a single power ramping counter is used, a condition in which the value of the counter is increased or maintained may be the presence or absence of a change in a transmission space beam direction for Msg A PRACH preamble transmission when Msg A is retransmitted. That is, if the transmission spatial beam direction for Msg A PRACH preamble transmission is the same as the previous transmission, the counter value increases, and if the transmission spatial beam direction for Msg A PRACH preamble transmission is different from the previous transmission, the counter value is maintained. do. In addition, in the case of using dual power ramping counters, the condition that the value of each counter increases or is maintained is in the transmission space beam direction compared to the previous transmission for Msg A PRACH preamble and Msg A PUSCH at the time of Msg A retransmission. It can be with or without change. That is, for Msg A PRACH preamble and Msg A PUSCH, if the transmission spatial beam direction for transmission of each signal is the same as the previous transmission, the value of each counter increases, and the transmission spatial beam direction for transmission of each signal is If it is different from the previous transmission, the value of each counter is maintained.

For reference, the term'retry' referred to in the present disclosure below means that the original RO cannot transmit the Msg A PRACH preamble due to the LBT failure, and the next RO transmits the Msg A PRACH preamble, or the original RO due to the LBT failure. This means that the PO fails to transmit the Msg A PUSCH and the next PO transmits the Msg A PUSCH. Although it is not possible to transmit the original Msg A PRACH preamble due to LBT failure, the case of transmitting another Msg A PRACH preamble from the originally scheduled RO does not mean'retry' mentioned in the present disclosure, and in this case, the value of the counter Again, it does not increase. The increase and maintenance of the power ramping counter for the retransmission of each signal included in Msg A, the maximum number of retransmissions, and the operation of the UE and the base station according to LBT failure, hereinafter, LBT failure and Msg A PUSCH transmission before Msg A PRACH preamble transmission. The case of previous LBT failure can be divided and described.

1) LBT failure before transmission of Msg A PRACH preamble

When the UE uses a single power ramping counter for Msg A PRACH preamble and Msg A PUSCH, if LBT fails before Msg A PRACH preamble transmission, the UE transmits Msg A PRACH preamble and Msg A PUSCH in succession. According to the embodiments described above, a corresponding common power ramping counter value may be increased or maintained. In addition, when the terminal uses dual power ramping counters for Msg A PRACH preamble and Msg A PUSCH, if LBT fails before Msg A PRACH preamble transmission, the value of each counter for Msg A PRACH preamble and Msg A PUSCH is It can be independently increased or maintained. In particular, if the transmission spatial beam direction set for transmission of each signal is the same as the previous transmission, the value of each counter increases, and the transmission spatial beam direction set for transmission of each signal If this is different from the previous transmission, the value of each counter is maintained.

At this time, if the UE that failed LBT before transmitting the Msg A PRACH preamble wants to retry the transmission of Msg A, the UE may continuously transmit Msg A or fall-back in a 4-step transmission of only Msg 1. In addition, the operation of the terminal and the base station may vary according to each method.

(a) First, when the UE fails to transmit the Msg A PRACH preamble due to a failure in LBT for a specific RO, the UE may attempt to transmit the Msg A PRACH preamble again in the next RO. At this time, the terminal selects the SSB differently according to the measured channel for Msg A PRACH preamble transmission, and randomly selects the RAPID from the 2-step preamble set associated with the selected SSB to transmit the Msg A PRACH preamble. You can try. When a single power ramping counter is set, if the Msg A PRACH preamble is retransmitted according to the same transmission beam direction used in the previous Msg A PRACH preamble transmission, the value of the corresponding counter increases, and the previous Msg A PRACH If the Msg A PRACH preamble is retransmitted according to a beam direction different from the transmission beam direction used at the time of preamble transmission, the value of the corresponding counter is maintained the same as before. When dual power ramping counters are set, the values of each counter for Msg A PRACH preamble and Msg A PUSCH can be independently increased or maintained. If it is the same as the transmission transmission beam direction that was set for, the value of each counter increases, and if the transmission space beam direction to be set for transmission of each signal is different from the transmission transmission beam direction set for the previous transmission, each counter The value of is maintained.

(b) When the UE fails to transmit the Msg A PRACH preamble due to a failure in LBT for a specific RO, the UE may transmit only Msg 1, not the Msg A PRACH preamble, in the next RO. That is, the UE can fall back to a 4-step RACH procedure. In the case of an occupied channel for transmission of other terminals or other signals, the probability that the channel on which the next LBT can be performed is also occupied is high, so this method is the time for allocating PUSCH resources for Msg A. / This is a method of promoting efficient resource utilization by transmitting only Msg 1 without specifying a frequency resource. At this time, the UE transmits Msg 1 using the preamble index for the 2-step RACH procedure, but the base station waits until the maximum transmission time of the Msg A PUSCH based on the detection time of Msg A (waiting), and the corresponding time In the case of the expiration, Msg 2 is transmitted in response to Msg 1 and a 4-step RACH procedure is performed. Here, the transmission power of Msg 1 may be set based on the setting of Msg 1 used in the 4-step RACH procedure, such as target received power for Msg 1.

2) LBT failure before Msg A PUSCH transmission

When the terminal fails in LBT before Msg A PUSCH transmission, the operation of the terminal may vary depending on whether the PO is set including a time interval for the LBT or whether the PO is set excluding the time interval for the LBT.

At this time, if the PO has been set including the time interval for the LBT, the terminal may perform the LBT within the time interval for the LBT and transmit the Msg A PUSCH at the same time when the LBT is successful, or the time for the corresponding LBT. When LBT is performed within the interval and LBT is successful, an arbitrary signal is transmitted up to the preset Msg A PUSCH start symbol for channel monopoly until the time when the original Msg A PUSCH is intended to be transmitted, and then Msg A PUSCH from the Msg A PUSCH start symbol. It can also be transmitted.

On the other hand, if the PO has been set excluding the time interval for the LBT, if the terminal does not succeed in LBT until the start symbol of the corresponding PO by performing the LBT before the corresponding PO, the terminal is in the next PO as in the embodiments described below. Perform LBT for transmitting only Msg A PUSCH and attempt to transmit Msg A PUSCH, perform LBT again to transmit Msg A PRACH preamble at the next RO and retry transmission of Msg A, or transmit only Msg 1 Thus, it is possible to fall back to a 4-step RACH procedure.

(a) First, the UE may transmit only the Msg A PUSCH in consideration of the fact that the Msg A PRACH preamble has already been transmitted. At this time, the transmission time of the Msg A PUSCH is performed in the resource of the next PO when the Msg A PRACH preamble and the PO have a multiple to one mapping relationship or a one to one mapping relationship. At this time, since the UE does not retransmit the Msg A PRACH, the resource for Msg A PUSCH transmission uses the same Msg A PUSCH resource associated with the RAPID used for the previous transmission. However, in order to distinguish whether the transmission of Msg A PUSCH is retransmission due to LBT failure at a previous time or an attempt to transmit Msg A PUSCH at the current time, Msg A PUSCH must be able to include information on retransmission, and the base station also corresponds Based on the information, it should be possible to convey through Msg B the number of responses to the previous RAPID. In addition, the UE recognizes an attempt to transmit Msg A PUSCH due to LBT failure as retransmission, and according to the above-described embodiments for the case in which Msg A PRACH preamble and Msg A PUSCH are successively transmitted, the UE sets the transmission power of Msg A PUSCH. It is possible to increase or maintain the value of the power ramping counter for.

On the other hand, when the Msg A PRACH preamble and PO have a one-to-multiple mapping relationship, the UE transmits only the Msg A PUSCH by performing LBT before or within the plurality of POs. If channel estimation is possible between a plurality of POs, the value of the power ramping counter for Msg A PUSCH transmission power increases when the transmission space beam direction for Msg A PUSCH is the same as the previous transmission. It is maintained when the transmission spatial beam direction for the Msg A PUSCH is different from the previous transmission. In this case, when a dual power ramping counter is set for each of Msg A PRACH and Msg A PUSCH, the corresponding counter may indicate only a retransmission counter for Msg A PUSCH.

(b) The UE may newly select and transmit the Msg A PRACH preamble for LBT failure prior to transmission of the Msg A PUSCH, and may transmit the Msg A PUSCH from a PO associated therewith. In the case of the above-described method of transmitting only Msg A PUSCH, information on Msg A PRACH preamble transmission must be delivered through the contents of Msg A PUSCH, through which the base station determines whether or not the current LBT has failed of the terminal, and the current transmission time of the terminal There is a need for an additional mechanism that responds by distinguishing between the time of transmission and the past transmission and conveys related information. On the other hand, in the case of this method, if the terminal fails to transmit the Msg A PUSCH, the terminal can select and transmit the Msg A PRACH preamble from the next RO, and the base station predicts a TA (Timing Advance) value based on the corresponding Msg A PRACH preamble. Thus, reception of Msg A PUSCH can be expected. In this case, the transmission power for the Msg A PRACH preamble is the value of the power ramping counter for the UE to set the transmission power of the Msg A PUSCH according to the above-described embodiments for the case where the Msg A PRACH preamble and the Msg A PUSCH are continuously transmitted. Can be allocated based on increasing or maintaining. If dual power ramping counters are used, whether the power ramping counter for each signal is increased or maintained may be configured differently depending on whether the transmission spatial beam direction for each of Msg A PRACH preamble and Msg A PUSCH is changed. .

(c) Since the terminal has already transmitted the Msg A PRACH preamble, it is determined that the base station has only received the preamble and can expect only to receive a response to the Msg A PRACH preamble without transmitting the Msg A PUSCH. The terminal transmits Msg 1 using the preamble index for the 2-step RACH procedure, but the base station waits until the maximum transmission time of the Msg A PUSCH based on the detection time of Msg A (waiting), and the corresponding time has passed. In the case of (expire), the transmission failure due to LBT is determined and information necessary for transmission of Msg 3 is transmitted to the terminal through Msg B. The UE can also automatically predict a fallback to the 4-step RACH procedure because it has transmitted only the Msg A PRACH preamble, and expects information necessary for Msg 3 transmission to be received through Msg B. Thereafter, the terminal can receive Msg B and transmit Msg 3 using the information included therein.

Configuration of HARQ-ACK resources for Msg B

In the case of Msg B transmitted by the base station to the terminal, a response to a single terminal or multiple terminals is transmitted, so a resource for HARQ-ACK (Hybrid Automatic Repeat Request-Acknowledgement) transmission in the terminal The base station needs to specify. Hereinafter, PUCCH resource configuration for transmission of HARQ-ACK for Msg B of the UE will be described.

In the 4-step RACH procedure on the NR system, the base station may use the PDCCH (DCI) of Msg 4 to designate a UE-specific resource for a PUCCH to be transmitted by the UE. When the PDCCH for scheduling Msg 4 is set to DCI format 1_0 scrambling with TC-RNTI (Temporary Cell-Radio Network Temporary Identifier), the DCI format 1_0 scrambled with RA-RNTI (Random Access-RNTI) Unlike the case, the following five DCI field elements excluding 1 bit for indicating the DCI format may be additionally indicated.

-TPC command for scheduled PUCCH-2 bits as defined in Subclause 7.2.1 of TS38.213

-PUCCH resource indicator-3 bits as defined in Subclause 9.2.3 of TS38.213

-PDSCH-to-HARQ_feedback timing indicator-3 bits a s defined in Subclause 9.2.3 of TS38.213

-　　 HARQ process number-4 bits

-　　 Downlink assignment index-2 bits, reserved

Specifically, among the above field elements indicated by DCI, a PUCCH resource indicator of up to 3 bits and a PDSCH-to-HARQ_feedback timing indicator of 3 bits may be used for the indication of PUCCH resources.

Here, the PDSCH-to-HARQ_feedback timing indicator is used to indicate the slot interval between the PDSCH including Msg 4 and the PUCCH including the HARQ-ACK to be transmitted by the UE, {0, 1, 2, 3, 4, 5, 6, 7 } One of the values can be indicated. For example, if the last slot in which the PDSCH containing Msg 4 is received is #n, the PDSCH-to-HARQ_feedback timing indicator is one of {0, 1, 2, 3, 4, 5, 6, 7} Is indicated as a slot interval k, and the UE transmits a PUCCH including HARQ-ACK in slot #n+k. A detailed indication method of the PDSCH-to-HARQ_feedback timing indicator is as follows.

In addition, the PUCCH resource indicator is used to indicate various parameters for setting PUCCH resources, and in dl-DataToUL-ACK SEQUENCE (SIZE (1..8)) OF INTEGER (0..15) of the upper layer parameter PUCCH-Config. The mapped resource is used according to the bit for each bit. The PUCCH resource indicator is 3 bits, and when indicating a specific set through RMSI (Remaining Minimum System Information) for two sets consisting of each of 8 resources, one PUCCH of the corresponding sets is set. Exists to do.

Like the 4-step RACH procedure above, the 2-step RACH procedure may require a method of designating the PUCCH resource as a response to Msg B. In particular, in the following, DCI or MAC ( Medium Access Control) A method of utilizing Msg B may be considered. Since a total of 16 PUCCH resources can be configured from index 0 to 15 for the PUCCH resource at any one point in time, when the base station transmits Msg B, Msg B must be configured and transmitted in consideration of the corresponding PUCCH resource. In addition, in the following disclosure, when the initial PUCCH resource index is designated as n and terminals are sequentially allocated from index n, each terminal may be cyclically allocated from index 0 to n if the PUCCH resource index exceeds 15. .

(1) Indicate PUCCH resources through DCI only

This method is a method of specifying a PUCCH resource to be used for HARQ-ACK transmission of the terminal by using only the DCI scheduling Msg B. At this time, the base station indicates only the PDSCH-to-HARQ_feedback timing indicator through DCI and allows the terminal to calculate the PUCCH resource implicitly, or through the DCI, the PDSCH-to-HARQ_feedback timing indicator and the initial PUCCH resource index Alternatively, the PUCCH resource indicator may be explicitly indicated.

1) First, the base station may designate only the slot in which the PUCCH is to be transmitted by indicating the slot interval with the PDSCH-to-HARQ_feedback timing indicator among the DCI fields of Msg B. All UEs related to the corresponding Msg B transmit HARQ-ACK for Msg B reception in the designated slot through this PDSCH-to-HARQ_feedback timing indicator, and at this time, the PUCCH resource index is the index order of the MAC subheader. And can be sequentially mapped one-to-one. For example, a terminal detecting its RAPID and UE-ID in subheader #1 transmits HARQ-ACK through PUCCH resource index #1, and a terminal detecting its RAPID and UE-ID in subheader #2 Transmits HARQ-ACK through PUCCH resource index #2. Since the UE can implicitly know the PUCCH resource index through its subheader index, the present method has the advantage of greatly reducing the signaling overhead of the base station.

2) The base station indicates the slot to which the PUCCH is to be transmitted by indicating the slot interval with the PDSCH-to-HARQ_feedback timing indicator among the DCI fields of Msg B, and may set the initial PUCCH resource index. At this time, the base station directly indicates the PUCCH resource using 4 bits for the PUCCH resource index having a value of 0 to 15, or indirectly indicates the PUCCH resource using the PUCCH resource indicator similar to the 4-step RACH procedure. May be.

In the above-described method in which the base station indicates only the PDSCH-to-HARQ_feedback timing indicator, PUCCH resource indexes #0 to 15 are sequentially allocated unconditionally, but in this method, the base station designates the initial value of the PUCCH resource index, and the terminal is designated. Based on the index of the initial value, the index of the MAC subheader is sequentially mapped one-to-one to receive the PUCCH resource index. For example, if PUCCH resource index #15 is specified in the DCI field, the UE detecting its RAPID and UE-ID in #1 subheader of Msg B transmits HARQ-ACK through PUCCH resource index #15, The UE that detects its RAPID and UE-ID in #2 subheader transmits HARQ-ACK through PUCCH resource index #0. In addition, the UE that detects its RAPID and UE-ID in #3 subheader transmits HARQ-ACK through PUCCH resource index #1.

3) In the case of the aforementioned 1) or 2) methods, all 16 PUCCH resource indexes are sequentially allocated, so even if an unusable PUCCH resource index exists, the base station cannot indicate the corresponding PUCCH resource index. To compensate for this, an unusable PUCCH resource index may be additionally indicated by using bits or bitmaps corresponding to the PUCCH resource index. That is, a PUCCH resource indicator (PRI) is sequentially allocated to the UE in the order of a MAC Protocol Data Unit (PDU), but a portion having a value of '0' among the additionally indicated bitmaps may be omitted and the PRI may be allocated. For example, if the bitmap for indicating the unusable PUCCH resource index is '1011111111111111', the terminal detecting its RAPID and UE-ID in #2 subheader of Msg B has the second bit value of the above bitmap. Because it is '0', PUCCH resource index #2 is omitted and HARQ-ACK is transmitted through PUCCH resource index #3, and the UE detecting its RAPID and UE-ID in subheader #3 is through PUCCH resource index #4. HARQ-ACK is transmitted.

(2) Indicate PUCCH resource through only MAC Msg B

This method is for setting a PDSCH-to-HARQ_feedback timing indicator (3 bits) and a PUCCH resource index (4 bits) or a PUCCH resource indicator (3 bits) for each terminal when the base station transmits the MAC Msg B (success RAR). This is a method of explicitly indicating 6-bit or 7-bit information through Msg B (success RAR).

That is, according to the present method, when the RAR message received by the UE through Msg B is successRAR, a PUCCH transmission resource is indicated by a 4-bit PUCCH resource related indication field in successRAR, and a 3-bit PDSCH in successRAR PUCCH transmission resources may be indicated by the -to-HARQ feedback timing indication field. In the case of this method, there is a disadvantage that the size of the MsgB (success RAR) increases as the MsgB (success RAR) contains a plurality of pieces of information, but the base station has the advantage of being able to specify the PUCCH resource of each terminal with full flexibility. have.

(3) PUCCH resources are indicated using both DCI and MAC Msg B

This method uses both DCI and MAC Msg B (success RAR) in a way that takes advantage of the above-described methods (1) and (2), excluding the extremes. The method may have various embodiments as follows depending on which information of the PDSCH-to-HARQ_feedback timing indicator and parameters such as a PUCCH resource index or a PUCCH resource indicator is transmitted through which information among DCI and MAC Msg B (success RAR).

1) First, PDSCH-to-HARQ_feedback timing indicator (3 bits) and PUCCH resource index (4 bits) or PUCCH resource indicator (3 bits) are included in DCI, and the PUCCH resource offset value of 1 bit or 2 bits is MAC Msg B You can consider being included in the (success RAR) and delivered.

In this case, the PDSCH-to-HARQ_feedback timing indicator parameter is basically transmitted by DCI, which increases signaling overhead, but it can be compensated by specifying a PUCCH resource offset value for each terminal in MAC Msg B (success RAR). have. The PUCCH resource index or the PUCCH resource indicator is also transmitted by DCI, so that the initial PUCCH resource index can be designated as in the above-described methods. Here, in the corresponding method, the offset value indicated by MAC Msg B (success RAR) may be N bits, and the offset may be used in the following ways.

(a) The offset indicated by MAC Msg B (success RAR) may be applied and utilized for the original UE's own PRI value. That is, the UE may transmit HARQ-ACK through a PUCCH resource corresponding to a PRI value to which an offset value is applied based on its own PRI index.

Based on the initial PUCCH resource index designated through DCI, the UE is sequentially assigned its own PUCCH resource index according to the subheader index of MAC Msg B (success RAR), and the UE receives MAC Msg B (success RAR). If the offset is indicated through the UE transmits the HARQ-ACK in the PUCCH resource of the index increased or decreased by the corresponding offset value.

For example, when the bit indicating the offset is 1, the offset value may be +1 or =1. When the bit representing the offset is 2, the offset value indicates a value of {+2, +1, -1, -2}, a value of {+4, +3, +2, +1}, or Values of {-4, -3, -2, -1} can be indicated. If the initial PUCCH resource index is #M, the UE that detects its RAPID and UE-ID in the K-th subheader is originally assigned the PUCCH resource index #M+K, and if the value of #M+K is greater than 15, the cyclic shift It means that a value according to is allocated, and the UE transmits HARQ-ACK in the PUCCH resource of the #M+K+a or #M+Ka index by applying the offset value a as described above.

(b) The offset indicated by MAC Msg B (success RAR) may be applied and utilized based on the location of the previous terminal. That is, in a state in which the accumulated offsets for previous terminals are applied as they are, the PUCCH resource to be used may be determined by additionally applying an offset indicated for the MAC subheader of the terminal itself.

For example, in a situation where the initial PUCCH resource index is #M, if the first terminal that detects its RAPID and UE-ID through the first subheader receives an offset of 3, the corresponding first terminal is #M+3. HARQ-ACK is transmitted in the PUCCH resource of the index. At this time, if the second terminal, which has detected its RAPID and UE-ID through the second subheader, receives an offset of 2, the second terminal accumulates and applies the offset value 3 applied to the first terminal. As #M+3+2, HARQ-ACK is transmitted in the PUCCH resource.

2) As another embodiment, only the PDSCH-to-HARQ_feedback timing indicator (3 bits) is included in the DCI, and each PRI for indicating the PUCCH resource index (4 bits) or the PUCCH resource indicator (3 bits) is MAC Msg B ( success RAR).

That is, in this embodiment, a common PUCCH transmission slot is transmitted through DCI, and a PUCCH resource index or a PUCCH resource indicator for each terminal is designated to be terminal-specific (UE specific) through MAC Msg B (success RAR). According to the present embodiment, signaling overhead may be increased compared to the above-described method of indicating an offset in a success RAR (MSg B), but flexibility in indicating a PUCCH resource of a base station may be increased.

3) As another embodiment, only PUCCH resource index (4 bits) or PUCCH resource indicator (3 bits) is included in DCI, and each PDSCH-to-HARQ_feedback timing indicator (3 bits) is in MAC Msg B (success RAR). You can consider what to include.

In this embodiment, the time (slot) setting of each PUCCH resource is differently classified. That is, when the base station designates a DCI common PUCCH resource index and uses the PUCCH resource according to the corresponding index, or if the information of the PUCCH resource index is not included in the DCI, all terminals initially use the PUCCH resource according to the PUCCH resource index #0. , Each UE transmits a PUCCH through a corresponding slot with reference to a slot timing determined according to information included in MAC Msg B (success RAR).

20 is a diagram for describing an example of an operation implementation of a terminal according to the present disclosure. Referring to FIG. 20, the terminal may transmit a message A including a first physical random access channel (PRACH) and a first physical uplink shared channel (PUSCH) based on transmission power set by a power ramping counter. Yes (S2001). In response to the message A, a message B including contention resolution information may be received (S2003). In this case, a specific method for the UE of S2001 to S2003 to transmit the message A and receive the message B may be based on the above-described embodiments and features.

Meanwhile, the terminal of FIG. 20 may be any one of various wireless devices disclosed in FIGS. 1 to 4. For example, the terminal of FIG. 20 may be the first wireless device 100 of FIG. 1 or the wireless devices 100 and 200 of FIG. 2. In other words, the operation process of FIG. 20 may be performed and executed by any one of various wireless devices disclosed in FIGS. 1 to 4.

21 is a diagram for describing an example of an operation implementation of a base station according to the present disclosure. Referring to Figure 21, the base station receives a message A including a first PRACH (Physical Random Access Channel) and a first PUSCH (Physical Uplink Shared Channel) (S2101), in response to the message A, contention resolution ( Contention resolution) message B including information may be transmitted (S2103). In this case, a specific method of receiving the message A and transmitting the message B by the base stations of S2101 to S2103 may be based on the above-described embodiments and features.

Meanwhile, the base station of FIG. 21 may be any one of various wireless devices disclosed in FIGS. 1 to 4. For example, the base station of FIG. 21 may be the second wireless device 200 of FIG. 1 or the wireless devices 100 and 200 of FIG. 2. In other words, the operation process of FIG. 21 may be performed and executed by any one of various wireless devices disclosed in FIGS. 1 to 4.

22 is a diagram illustrating an operation flow of a terminal and a base station for performing a 2-step RACH procedure based on embodiments of the present disclosure. The UE and the base station transmit and receive RACH configuration information for performing a 2-step RACH procedure, and the information includes a power ramping step size and/or a ramping counter, a transmission beam, or Information related to embodiments of the present disclosure, such as a spatial filter, may also be included (S2201). Specifically, the base station may transmit RACH configuration information using a synchronization signal block (SSB) such as a master information block (MIB) and a system information block (SIB), and/or RRC signaling.

The step S2201 may be omitted in the case of a terminal that has established a connection state, such as a terminal that has already received the above RACH configuration information or a terminal that reconnects to a base station that has transmitted the RACH configuration information. . Since the UEs have already obtained RACH Configuration information, a corresponding step may be omitted for these UEs to reduce a processing delay due to redundant transmission and reception of previously received RACH Configuration information.

The terminal in step S2201 described above may be the first wireless device 100 of FIG. 1 or the wireless devices 100 and 200 of FIG. 2, and the base station is the second wireless device 200 of FIG. 1 or the wireless device of FIG. 2. It may be (100, 200). That is, the step S2201 in which the terminal receives RACH configuration information from the base station may be implemented by various wireless devices of FIGS. 1 to 4 described above. For example, when the terminal corresponds to the first wireless device 100 of FIG. 1, the processor 102 of FIG. 1 may control one or more transceivers 106 and/or one or more memories 104 to receive the RACH configuration information. , The one or more transceivers 106 may receive the RACH Configuration information from the base station.

Thereafter, the UE can acquire information about Msg A based on the RACH configuration received from the base station, and according to the acquired information, RACH Occasion (RO)/Preamble and PUSCH Occasion (PO)/PUSCH resource unit Msg A for performing a 2-step RACH procedure by selecting (PRU) may be transmitted to the base station (S2203). Here, the terminal may transmit Msg A based on a ramping step size for setting the transmission power of Msg A and/or a counter, a transmission beam, or a spatial filter related to the embodiments of the present disclosure.

The terminal in step S2203 described above may be the first wireless device 100 of FIG. 1 or the wireless devices 100 and 200 of FIG. 2, and the base station is the second wireless device 200 of FIG. 1 or the wireless device of FIG. 2. It may be (100, 200). That is, the step S2203 in which the terminal transmits Msg A to the base station may be implemented by various wireless devices of FIGS. 1 to 4 described above. For example, when the terminal corresponds to the first wireless device 100 of FIG. 1, the processor 102 of FIG. 1 may control one or more transceivers 106 and/or one or more memories 104 to transmit the Msg A, The one or more transceivers 106 may transmit the Msg A to the base station.

In this case, as an example of the transmission of Msg A in step S2203, the RO in the 2-step RACH procedure considers the RO allocated for the 4-step RACH procedure, i) 2-step RACH Procedure and 4-step RACH Procedure Independent RO and preamble are set for each, ii) share the same RO for 2-step RACH Procedure and 4-step RACH Procedure, but preamble is set separately, or iii) 2-step RACH Procedure and 4-step It can be configured to share the same RO and preamble for RACH Procedure.

As another example of the Msg A transmission in step S2203, the PRU for transmission of the Msg A PUSCH may be defined in consideration of the PO, the DMRS port, and the DMRS sequence, and the PO is a time-frequency for payload transmission. It can be defined as a resource. At this time, the PO for the PUSCH of Msg A may be set separately from the RO, or may be set as a relative time and/or frequency position in consideration of the associated RO, and one or more PO(s) may be set within the setting period of the Msg A PUSCH. I can.

As another example of the transmission of Msg A in step S2203, PRACH and PUSCH included in Msg A may be time division multiplexed (TDM) and transmitted in different slots, or PRACH and PUSCH may be transmitted in the same slot. May be. In other words, the Msg A PUSCH may be continuously transmitted on the time domain with the Msg A PRACH or may be transmitted with a specific gap.

As another example of the transmission of Msg A in step S2203, the PRACH and PUSCH included in Msg A are i) transmitted using the same beam or a spatial filter (Tx spatial filter), or ii) according to the decision of the terminal. It may be transmitted using the same or different beam or spatial filter, or iii) transmitted using a beam or spatial filter set by the base station.

As another example of the transmission of Msg A in step S2203, the terminal may set a random access response (RAR) window for monitoring Msg B after Msg A is transmitted. In this case, in order to record the number of retries of the 2-step RACH procedure, the terminal may set a retransmission counter of Msg A, and the maximum value of the counter may be set by the base station or the network.

As another example of the Msg A transmission in step S2203, the base station may detect the preamble of the Msg A PRACH and decode the payload/data of the Msg A PUSCH and process it. If the base station does not detect the preamble of the Msg A PRACH, the base station may not deliver any information to the terminal.

As described above, in step S2203 in which the terminal transmits Msg A to the base station, embodiments of the present disclosure may be appropriately applied. Specifically, the transmission power for the Msg A may be set or indicated based on the method in the embodiments of the present disclosure described above.

The terminal that has transmitted Msg A may then receive Msg B (S2205). Here, Msg B may be scheduled through a PDCCH corresponding to the DMRS and transmitted through a PDSCH corresponding to the DMRS. Information (contents) included in Msg B may vary according to a result of decoding and processing of Msg A PUSCH.

Specifically, when the base station successfully decodes the Msg A PUSCH, Msg B is a success RAR and a contention resolution identifier such as a UE identifier transmitted by the UE as a Common Control Channel (CCCH) Service Data Unit (SDU) ( When the base station fails to decode the Msg A PUSCH, Msg B is a fallback RAR and includes RAPID and uplink grant (UL grant) information for retransmission of the PUSCH of Msg A. When the base station transmits a fallback RAR through Msg B, the UE having successfully decoded the RAPID and UL grant included in Msg B may fall-back with a 4-step RACH procedure.

The terminal in step S2205 described above may be the first wireless device 100 of FIG. 1 or the wireless devices 100 and 200 of FIG. 2, and the base station is the second wireless device 200 of FIG. 1 or the wireless device of FIG. 2. It may be (100, 200). That is, the step S2205 in which the terminal receives Msg B from the base station may be implemented by various wireless devices of FIGS. 1 to 4 described above. For example, when the terminal corresponds to the first wireless device 100 of FIG. 1, the processor 102 of FIG. 1 may control one or more transceivers 106 and/or one or more memories 104 to receive the Msg B, The one or more transceivers 106 may receive the Msg B to the base station.

The UE may take the same or similar operation as the operation after the UE performing the existing 4-step RACH procedure receives Msg 4 according to whether Msg B is decoded and received. If the terminal successfully receives Msg B in the RAR window, the terminal may determine that the 2-step RACH procedure has been successful. Or, when the UE receives the fallback RAR, the UE may perform the Msg 3 transmission procedure on the 4-step RACH Procedure based on information included in Msg B such as UL grant.

On the other hand, if the terminal does not receive Msg B in the RAR window, the terminal can retransmit Msg A to retry the 2-step RACH procedure if the retransmission counter is less than the maximum value, and the retransmission counter reaches the maximum value. If so, it is determined that the 2-step RACH procedure has failed and the back-off operation can be performed. Here, retransmission of Msg A may mean retransmission of Msg A PRACH including reselection of preamble and retransmission of Msg A PUSCH. If the transmission beam or spatial filter for retransmission of the Msg A PRACH is different from the transmission beam or spatial filter of the recently transmitted Msg A PRACH, the power ramping counter of the Msg A PRACH may not increase.

The embodiments related to the 2-step RACH procedure of the present disclosure described above may be applied even in the RRC_INACTIVE, RRC_CONNECTED, and RRC_IDLE states, and may be configured as a general Medium Access Control (MAC) procedure. In addition, embodiments related to the 2-step RACH procedure of the above-described disclosure may not be exceptionally applied to the system information (SI) request and/or the beam failure recovery (BFR) procedure. In addition, an operation for re-performing the existing 4-step RACH procedure in consideration of fall-back in the above-described 2-step RACH procedure may be configured.

The embodiments described above are those in which constituent elements and features of the present invention are combined in a predetermined form. Each component or feature should be considered optional unless explicitly stated otherwise. Each component or feature may be implemented in a form that is not combined with other components or features. In addition, it is possible to configure an embodiment of the present invention by combining some components and/or features. The order of operations described in the embodiments of the present invention may be changed. Some configurations or features of one embodiment may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments. It is apparent that claims that do not have an explicit citation relationship in the claims may be combined to constitute an embodiment or may be included as a new claim by amendment after filing.

Here, the wireless communication technology implemented in the wireless device of the present specification may include LTE, NR, and 6G as well as NB-IoT (Narrowband Internet of Things) for low power communication. At this time, for example, the NB-IoT technology may be an example of LPWAN (Low Power Wide Area Network) technology, and may be implemented in standards such as LTE Cat (Category) NB1 and/or LTE Cat NB2, and It is not limited. Additionally or alternatively, the wireless communication technology implemented in the wireless device of the present specification may perform communication based on the LTE-M technology. In this case, as an example, the LTE-M technology may be an example of an LPWAN technology, and may be referred to by various names such as enhanced machine type communication (eMTC). For example, LTE-M technology is 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-Bandwidth Limited (BL), 5) LTE-MTC, 6) LTE Machine Type Communication, and/or 7) may be implemented in at least one of various standards such as LTE M, and is not limited to the above-described name. Additionally or alternatively, the wireless communication technology implemented in the wireless device of the present specification includes at least one of ZigBee, Bluetooth, and Low Power Wide Area Network (LPWAN) in consideration of low power communication. It can be, and is not limited to the above-described name. For example, ZigBee technology can create personal area networks (PANs) related to small/low-power digital communication based on various standards such as IEEE 802.15.4, and may be referred to by various names.

A specific operation described as being performed by a base station in this document may be performed by its upper node in some cases. That is, it is apparent that various operations performed for communication with a terminal in a network comprising a plurality of network nodes including a base station may be performed by the base station or other network nodes other than the base station. The base station may be replaced by terms such as a fixed station, gNode B (gNB), Node B, eNode B (eNB), and access point.

It is obvious to those skilled in the art that the present invention can be embodied in other specific forms without departing from the features of the present invention. Therefore, the detailed description above should not be construed as restrictive in all respects and should be considered as illustrative. The scope of the present invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the present invention are included in the scope of the present invention.

The method and apparatus for receiving the downlink control channel in the unlicensed band as described above have been described with a focus on an example applied to the 5th generation NewRAT system, but it can be applied to various wireless communication systems in addition to the 5th generation NewRAT system. Do.

Claims (15)

In the method for the UE to receive a downlink control channel (Physical Downlink Control Channel; PDCCH) in an unlicensed band (Unlicensed band), SS/PBCH (Synchronization Signal/PBCH) block including Primary Synchronization Signal (PSS), Secondary Synchronization Signal (SSS), and Physical Broadcast Channel (PBCH) is received from the base station, Based on the system information included in the PBCH of the SS/PBCH block, a first PRACH (Physical Random Access Channel) and a first PUSCH (Physical Uplink Shared Channel) are selected according to transmission power set by a power ramping counter. Transmits the included message A to the base station, In response to the message A, a message B related to contention resolution is received from the base station, and a random access procedure (RACH procedure) for the base station is performed, and The PDCCH is received from the base station in on-duration according to the DRX, based on the point in which the DRX (Discontinuous Reception) is set in the terminal, The value of the power ramping counter is increased based on the fact that a transmission spatial beam for transmission of the message A is configured to be the same as a transmission spatial beam related to transmission of a PRACH before the message A, How to receive PDCCH. The method of claim 1, The value of the power ramping counter is increased based on the point that the LBT (Listen Before Talk) for the message A has not failed, How to receive PDCCH. The method of claim 1, The transmission of the message A corresponds to the retransmission of the message A, How to receive PDCCH. The method of claim 1, LBT (Listen Before Talk) related to the PRACH has failed, How to receive PDCCH. The method of claim 1, Based on the fact that the transmission spatial beam for transmission of the message A is configured differently from the transmission spatial beam related to transmission of the PRACH before the message A, the value of the power ramping counter does not increase, How to receive PDCCH. The method of claim 1, The power ramping counter is used to set the transmission power based on the point that the first PRACH and the first PUSCH are transmitted together through the message A, How to receive PDCCH. In the terminal receiving a downlink control channel (Physical Downlink Control Channel; PDCCH) in the unlicensed band (Unlicensed band), At least one transceiver; At least one processor; And At least one memory that is operably connected to the at least one processor and stores instructions for causing the at least one processor to perform a specific operation when executed; and The specific operation is, SS/PBCH (Synchronization Signal/PBCH) block including Primary Synchronization Signal (PSS), Secondary Synchronization Signal (SSS), and Physical Broadcast Channel (PBCH) is received from the base station, Based on the system information included in the PBCH of the SS/PBCH block, a first PRACH (Physical Random Access Channel) and a first PUSCH (Physical Uplink Shared Channel) are selected according to transmission power set by a power ramping counter. Transmits the included message A to the base station, In response to the message A, a message B related to contention resolution is received from the base station, and a random access procedure (RACH procedure) for the base station is performed, and The PDCCH is received from the base station in on-duration according to the DRX, based on the point in which the DRX (Discontinuous Reception) is set in the terminal, The value of the power ramping counter is increased based on the fact that a transmission spatial beam for transmission of the message A is configured to be the same as a transmission spatial beam related to transmission of a PRACH before the message A, Terminal. The method of claim 7, The value of the power ramping counter is increased based on the point that the LBT (Listen Before Talk) for the message A has not failed, Terminal. The method of claim 7, The transmission of the message A corresponds to the retransmission of the message A, Terminal. The method of claim 7, LBT (Listen Before Talk) related to the PRACH has failed, Terminal. The method of claim 7, Based on the fact that the transmission spatial beam for transmission of the message A is configured differently from the transmission spatial beam related to transmission of the PRACH before the message A, the value of the power ramping counter does not increase, Terminal. The method of claim 7, The power ramping counter is used to set the transmission power based on the point that the first PRACH and the first PUSCH are transmitted together through the message A, Terminal. In the apparatus for receiving a downlink control channel (Physical Downlink Control Channel; PDCCH) in an unlicensed band (Unlicensed band), At least one transceiver; At least one processor; And At least one memory that is operably connected to the at least one processor and stores instructions for causing the at least one processor to perform a specific operation when executed; and The specific operation is, Receiving an SS/PBCH (Synchronization Signal/PBCH) block including a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH), Based on the system information included in the PBCH of the SS/PBCH block, a first PRACH (Physical Random Access Channel) and a first PUSCH (Physical Uplink Shared Channel) are selected according to transmission power set by a power ramping counter. Send the containing message A, In response to the message A, a message B related to contention resolution is received, and a random access procedure (RACH procedure) is performed, and Based on a point in which a discontinuous reception (DRX) is set in the device, the PDCCH is received in on-duration according to the DRX, The value of the power ramping counter is increased based on the fact that a transmission spatial beam for transmission of the message A is configured to be the same as a transmission spatial beam related to transmission of a PRACH before the message A, Device. In the method for a base station to transmit a downlink control channel (Physical Downlink Control Channel; PDCCH) in an unlicensed band (Unlicensed band), SS/PBCH (Synchronization Signal/PBCH) block including Primary Synchronization Signal (PSS), Secondary Synchronization Signal (SSS), and Physical Broadcast Channel (PBCH) is transmitted to the terminal, A message A including a first physical random access channel (PRACH) and a first physical uplink shared channel (PUSCH) is received from the terminal, In response to the message A, a message B related to contention resolution is transmitted to the terminal, Including transmitting the PDCCH to the terminal in On-duration for DRX (Discontinuous Reception) operation, The transmit power of the message A is set based on a power ramping counter, The value of the power ramping counter is increased based on the fact that a transmission spatial beam for transmission of the message A is configured to be the same as a transmission spatial beam related to transmission of a PRACH before the message A, PDCCH transmission method. A computer-readable storage medium, comprising: The computer-readable storage medium stores at least one computer program including instructions for causing the at least one processor to perform operations for a user device, when executed by at least one processor, The above operations are: Receiving an SS/PBCH (Synchronization Signal/PBCH) block including a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH), Based on the system information included in the PBCH of the SS/PBCH block, a first PRACH (Physical Random Access Channel) and a first PUSCH (Physical Uplink Shared Channel) are selected according to transmission power set by a power ramping counter. Send the containing message A, In response to the message A, a message B related to contention resolution is received, and a random access procedure (RACH procedure) is performed, and Based on the point in which the DRX (Discontinuous Reception) is set, a downlink control channel (Physical Downlink Control Channel; PDCCH) is received in On-duration according to the DRX, The value of the power ramping counter is increased based on the fact that a transmission spatial beam for transmission of the message A is configured to be the same as a transmission spatial beam related to transmission of a PRACH before the message A, Computer readable storage media.

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